CONSTRUCTION OF ELECTRICAL REMOTE CONTROL MOTOR CAR
PREPARED BY:

Soyombo oluwajuwonlo gabriel 2018702030240
Sangodoyin ajibola mujeeb 2018702030237
Sowunmi sunday Joseph 2018702030239
Sunmonu akinkunmi quadri 2018702030241
Fadare temitayo Lawrence. 2018702030121
Oyelabi Timileyin Samuel. 2016070203234

A PROJECT REPORT SUBMITTED OF ELECTRICAL ENGINEERING IN PARTIAL FULFILLMENT FOR THE AWARD OF NATIONAL DIPLOMA
FACULTY OF ENGINEERING
THE POLYTECHNIC IBADAN

MARCH, 2021.

AUTHENTICATION

I hereby certify that this project work “CONSTRUCTION OF A REMOTE CONTROL MOTOR CAR” was carried out by:

Soyombo oluwajuwonlo gabriel 2018702030240
Sangodoyin ajibola mujeeb 2018702030237
Sowunmi sunday Joseph 2018702030239
Sunmonu akinkunmi quadri 2018702030241
Fadare temitayo Lawrence. 2018702030121
Oyelabi Timileyin Samuel. 2016070203234

of the Department of Electrical Engineering, The Polytechnic, Ibadan.

________ ____
MR. S.O. OLAYIWOLA
Supervisor

________ ____
ENGR. M.O. SADIQ
Head of Department

TABLE OF CONTENTS

TITLE PAGE. i
AUTHENTICATION ii
TABLE OF CONTENT. iii
CHAPTER ONE
1.1 INTRODUCTION 1
1.2 BACKGROUND OF THE PROJECT 1
1.3 PROBLEM STATEMENT 1
1.4 AIM OF THE PROJECT 2
1.5 OBJECTIVE OF THE PROJECT 2
1.6 SIGNIFICANCE OF THE PROJECT 2
1.7 BENEFIT OF THE STUDY 2
1.8 LIMITATION OF THE PROJECT 2
1.9 DEFINITION OF TERM 3
CHAPTER TWO
2.0 LITERATURE REVIEW 4
2.1 LITERATURE REVIEW OF REMOTE TECHNOLOGY 4
2.2 HISTORICAL BACKGROUND OF REMOTE CONTROL 5
2.3 REVIEW OF DIFFERENT TYPES OF REMOTE CONTROL CAR 9
CHAPTER THREE
3.0 METHODOLOGY 12
3.1 INTRODUCTION 12
3.2 BLOCK DIAGRAM OF THE SYSTEM 12
3.3 BLOCK DESCRIPTION 13
3.4 ELECTRONIC COMPONENTS USED 14
3.5 CIRCUIT DESIGN OF REMOTE CONTROL CAR 14
REFERENCE 18

ABSTRACT

This work is on a remote control motor car. Remote controlled car is battery/ powered model cars or trucks that can be controlled from a distance using a specialized transmitter or remote. This Radio controlled system is adopted in many vehicles like cars, boats, planes, and even helicopters and scale railway locomotives. In this work we will use a couple of ICs and a motor fixed to a chassis to make a remote control car. This work involve a brief idea is to transmit control signals through radio frequency and receive it through a receiver module in the car. We will have two switches in our remote control to power each motor of the car.

The objective of this project is to design a low cost remote control toy or robot. In this work we shall assemble the motors, circuit, and wheels on the chassis.

TABLE OF CONTENTS
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWELDGEMENT
ABSTRACT
TABLE OF CONTENT
CHAPTER ONE
INTRODUCTION
BACKGROUND OF THE PROJECT
PROBLEM STATEMENT
AIM OF THE PROJECT
OBJECTIVE OF THE PROJECT
SIGNIFICANCE OF THE PROJECT
BENEFIT OF THE STUDY
LIMITATION OF THE PROJECT
PROJECT ORGANISATION

CHAPTER TWO
LITERATURE REVIEW
2.0 LITERATURE REVIEW
2.1 LITERATURE REVIEW OF REMOTE TECHNOLOGY
2.2 HISTORICAL BACKGROUND OF REMOTE CONTROL
2.4 REVIEW OF DIFFERENT TYPES OF REMOTE CONTROL CAR

CHAPTER THREE
3.0 METHODOLOGY
3.1 INTRODUCTION
3.2 BLOCK DIAGRAM OF THE SYSTEM
3.3 BLOCK DESCRIPTION
3.4 ELECTRONIC COMPONENTS USED
3.5 CIRCUIT DESIGN OF REMOTE CONTROL CAR

CHAPTER FOUR
RESULT ANALYSIS
4.1 CONSTRUCTION PROCEDURE
4.2 ASSEMBLING OF SECTIONS
4.3 MOUNTING PROCEDURE
4.4 TESTING
4.5 RESULT
4.6 ECONOMIC OF THE PROJECT
4.7 RELIABILITY
4.8 MAINTAINABILITY
4.9 PROJECT EVALUATION
4.10 BILL OF ENGINEERING MEASUREMENTS AND EVALUATION

CHAPTER FIVE
CONCLUSIONS
RECOMMENDATION
5.3 REFERENCES

CHAPTER ONE

1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Remote control car referred to as RC Car, RC is short for Radio control or Remote control. In Europe, Japan and Southeast Asian countries, the remote control model car race is a kind of sports competitions and a noble sport, even a high-tech hobby. This is a competition from age limit because enthusiasts who participate in this sport is aged from 8 to 80 years. This also suggests that the remote control cars is the same as remote control aircraft, whether adult or children can play. However, it has a certain degree of risk, because the remote control car is not a simple toy, its principle is the same as the real car. So, I still recommend that children would better to accompany by their parents.
Electric remote control car is primarily provided power by an electric motor. Due to powered by a battery, it has higher overall operating efficiency and excellent acceleration performance of vehicles. Because of Clean Energy, the vehicle maintenance is very convenient, just pay attention to the maintenance of transmission parts. But because the electric motor remote control car need high requirements of motor performance and battery performance, so the motor and battery  consumption is very high in the beginning, coupled with the electronic speed control, remote equipment costs.
1.2 PROBLEM STATEMENT
Kids using manual car as fun or for recreation involved physical strength and sometimes can be hazardous in that they can be injured whenever the car crash with an object or obstacle. However, this device can overcome this problem. This device does not involve physical strength in that the motor is been controlled wirelessly using remote.
1.3 AIM OF THE PROJECT
This project was aimed at building a wireless remotely controlled motor car. It involves using a remote to control movement and direction of a car.
1.4 OBJECTIVES OF THE STUDY
The objective of this project is to design a low cost remote control toy or robot. There are so many projects available to make motor toys. But here we are providing a simple circuit with low cost electronics components.
1.5 SIGNIFICANCE OF THE STUDY
It is very useful to study the basics of wireless communication for electronics beginners. Mainly wireless car projects use two types of technologies Infra-Red (IR) and Radio Frequency (RF). IR remote control sends infrared rays to the car circuit. In case of IR remote control, line of sight with the receiving circuit is necessary and its range is only up to 10 meters. But in case of RF remote Radio Frequency waves plays the role, so signal can go through walls and are able to provide a range up to 35 meters.
1.6 BENEFIT OF THE STUDY
Playing with RC cars can significantly develop and improve a child’s visual-motor coordination. This is the ability to coordinate visual information with motor output. Along with this skill is visual perception, which is the ability to recognize, recall, discriminate and make sense of what we see.
RC car play enhances spatial awareness spatial intelligence and awareness skills, which results in increased dexterity. In addition, kids learn about cause-and-effect during play as they work out which buttons make the car go in each direction.
While playing with other children, it also teaches them to swerve around obstacles they can’t control.
And it is no stretch to say that playing with remote control cares promotes creativity and imagination. While adults may be content to have their cars zip around a parking lot, or engage in structured games or competition, kids tend to use their imagination and create make-believe settings and scenarios.
1.7 LIMITATION OF THE PROJECT
This device was able to provide a range up to 35 meters. To operate this device becomes a problem when the remote is faulty or whenever the battery of the remote runs down
1.8 DEFINITION OF TERMS
1. RF Transmitter: Amplitude shift keying (ASKRF) transmitter module is a small PCB sub-assembly capable of transmitting a radio wave and modulating that wave to carry data. Transmitter modules are usually implemented alongside a microcontroller which will provide data to the module which can be transmitted.
2. RF Receiver: Amplitude shift keying (ASK RF) Receiver serial data and transmits it wirelessly through its RF antenna. The transmission occurs at the rate of 1Kbps–10Kbps. RF receiver receives the transmitted data and it is operating at the same frequency as that of the transmitter.
3. HT12E Encoder IC: HT12E is used to encode the data for RF Transmitter and HT12D is used to decode the data received by RF receiver. Product Features. The HT12E Encoder IC are series of CMOSLS Is for Remote Control system applications. They are capable of Encoding 12 bit of information which consists of 8 address bits and 4data bits.
4. HT12D Decoder IC: HT12D is a 212series decoder IC (Integrated Circuit) for remote control applications manufactured by Holtek. It is commonly used for radio frequency (RF) wireless applications.
5. L293D Motor Driver: L293D is a typical Motor driver or Motor Driver IC which allows DC motor to drive on either direction. L293D is a 16-pin IC which can control a set of two DC motors simultaneously in any direction. It means that you can control two DC motor with a single L293DIC.
6. LED: Light Emmiting Diode it serves as flow of connection from the remote control to the motor car.
Resistor 1k: It resist the current of the motor, which serves as brake to the remote car
Battery: 9V/12V it is been used to power the circuit.

CHAPTER TWO

LITERATURE REVIEW
In this chapter all the literature and terms related to this work are reviewed.
2.1 LITERATURE REVIEW OF REMOTE TECHNOLOGY
By the early 1980s, the industry moved to infrared, or IR, remote technology. The IR remote works by using a low frequency light beam, so low that the human eye cannot see it, but which can be detected by a receiver in the TV. Zenith’s development of cable-compatible tuning and teletext technologies in the 1980s greatly enhanced the capabilities and uses for infrared television (TV) remotes. Today, remote control is a standard feature on other consumer electronics products, including video cassette recorders (VCRs), cable and satellite boxes, digital video disc players and home audio receivers. And the most sophisticated TV sets have remotes with as many as 50 buttons.
Zenith developed the world’s first wireless trackball TV remote control, called Z-Trak. The remote works like a computer mouse – click the ball and a cursor appears on the TV screen. Roll the ball and the cursor activates control menus hidden in different corners of the screen. Then, activate something from those menu bass, treble, contrast, colour temperature, and channel [5, 6, 7].
According to Sajidullah S. Khan, Anuja Khodustar and Koli, N.A who worked on Home automation appliance (2011) and striking results were obtained in terms of reduction in delay time between the transitions of streams from client to server using Java enabled program.
More so, Kai-Hung Liang, Kuo-Han Kan, and Szu-Chi Tien (2013) who carried out work on the precision positioning with shape-memory-alloy actuators. The result obtained using the inversion of non-linear model with model-reference-adaptive system (MRAS) was robust as regards to external disturbances and the positioning performance [1].
2.2 HISTORICAL BACKGROUND OF REMOTE CONTROL
The earliest example of remote control by radio waves was developed in 1898 by Nikola Tesla and described in his patent, U.S. Patent 613,809, named Method of an Apparatus for Controlling Mechanism of Moving Vehicle or Vehicles. In 1898, he demonstrated a radio-controlled boat to the public during an electrical exhibition at Madison Square Garden. Tesla called his boat a “teleautomaton”.
In 1903, Leonardo Torres Quevedo presented the Telekino at the Paris Academy of Science, accompanied by a brief, and making an experimental demonstration. In the same time he obtained a patent in France, Spain, Great Britain, and the United States. The Telekino consisted of a robot that executed commands transmitted by electromagnetic waves. With the Telekino, Torres-Quevedo laid down modern wireless remote-control operation principles and was a pioneer in the field of remote control. In 1906, in the presence of the king and before a great crowd, Torres successfully demonstrated the invention in the port of Bilbao, guiding a boat from the shore. Later, he would try to apply the Telekino to projectiles and torpedoes, but had to abandon the project for lack of financing.
The first remote-controlled model aeroplane flew in 1932, and the use of remote control technology for military purposes was worked intensively during the Second World War, one result of this being the German Waterfall missile.
By the late 1930s, several radio manufacturers offered remote controls for some of their higher-end models. Most of these were connected to the set being controlled by wires, but the Philco Mystery Control (1939) was a battery-operated low-frequency radio transmitter, thus making it the first wireless remote control for a consumer electronics device.
Television remote controls
The first remote intended to control a television was developed by Zenith Radio Corporation in 1950. The remote, called “Lazy Bones”, was connected to the television by a wire. A wireless remote control, the “Flashmatic”, was developed in 1955 by Eugene Polley. It worked by shining a beam of light onto a photoelectric cell, but the cell did not distinguish between light from the remote and light from other sources. The Flashmatic also had to be pointed very precisely at the receiver in order to work.[7]In 1956, Robert Adler developed “Zenith Space Command”, a wireless remote. It was mechanical and used ultrasound to change the channel and volume. When the user pushed a button on the remote control, it clicked and struck a bar, hence the term “clicker”. Each bar emitted a different frequency and circuits in the television detected this sound. The invention of the transistor made possible cheaper electronic remotes that contained a piezoelectric crystal that was fed by an oscillating electric current at a frequency near or above the upper threshold of human hearing, though still audible to dogs. The receiver contained a microphone attached to a circuit that was tuned to the same frequency. Some problems with this method were that the receiver could be triggered accidentally by naturally occurring noises, and some people could hear the piercing ultrasonic signals. There was an incident in which a toy xylophone changed the channels on such sets because some of the overtones from the xylophone matched the remote’s ultrasonic frequency.
The impetus for a more complex type of television remote control came in 1973, with th upe development of the Ceefax teletext service by the BBC. Most commercial remote controls at that time had a limited number of functions, sometimes as few as three: next channel,

previous channel, and volume/off. This type of control did not meet the needs of teletext sets, where pages were identified with three-digit numbers. A remote control to select teletext pages would need buttons for each numeral from zero to nine, as well as other control functions, such as switching from text to picture, and the normal television controls of volume, channel, brightness, colour intensity, etc. Early teletext sets used wired remote controls to select pages, but the continuous use of the remote control required for teletext quickly indicated the need for a wireless device. So BBC engineers began talks with one or two television manufacturers, which led to early prototypes in around 1977–1978 that could control many more functions. ITT was one of the companies and later gave its name to the ITT protocol of infrared communication.
In 1980, a Canadian company, Viewstar, Inc., was formed by engineer Paul Hrivnak and started producing a cable TV converter with an infrared remote control. At the time the most popular remote control was the Starcom of Jerrold (a division of General Instruments) which used 40-kHz sound to change channels. The Viewstar converter was an immediate success, the millionth converter being sold on March 21, 1985, with 1.6 million sold by 1989.
In 2006, Hillcrest Labs introduced the Loop pointer, a remote control that used Hillcrest’s Freespace motion control technology to allow users to control their televisions with natural gestures. The Loop had just four buttons and a scroll wheel. Freespace-enabled remote controls use radio waves to communicate with a USB antenna connected to a computer that is also connected to the television, so they do not need to be pointed at the PC, or even have a direct line of sight.
Some television manufacturers now include Bluetooth remotes to control the television without requiring line of sight, overcoming the limited range in IR-based remotes.
Effect of the early television remote control
The remote allowed audiences, for the first time, to interact with their TV without using the buttons on the TV. They no longer watched programs just because they did not want to get up to change the channel. They could also channel surf during commercials, or turn the sound off.
The invention of the remote control has led to several changes in television programming. One was the creation of split screen credits. According to James Gleick, an NBC research team discovered that when the credits started rolling after a program, 25% of its viewers would change the channel before it was over. Because of this, the NBC 2000 unit invented the “squeeze and tease” which squeezed the credits onto one third of the screen while the final minutes of the broadcast aired simultaneously.
The remote control also led to an adjustment in commercial airings. Networks began to feel that they could not afford to have commercials between programs because it would detract viewers from staying tuned into their channel. Programmers decided to place commercials in the middle of programs to make the transition to the next show direct.
Other remote controls
In the 1980s Steve Wozniak of Apple started a company named CL 9. The purpose of this company was to create a remote control that could operate multiple electronic devices. The CORE unit (Controller Of Remote Equipment) was introduced in the fall of 1987. The advantage to this remote controller was that it could “learn” remote signals from different devices. It had the ability to perform specific or multiple functions at various times with its built-in clock. It was the first remote control that could be linked to a computer and loaded with updated software code as needed.
The CORE unit never made a huge impact on the market. It was much too cumbersome for the average user to program, but it received rave reviews from those who could. These obstacles eventually led to the demise of CL 9, but two of its employees continued the business under the name Celadon. This was one of the first computer-controlled learning remote controls on the market.
The proliferation of remote controls
By the early 2000s, the number of consumer electronic devices in most homes greatly increased, along with the number of remotes to control those devices. According to the Consumer Electronics Association, an average American home has four remotes. To operate a home theater as many as five or six remotes may be required, including one for cable or satellite receiver, VCR or digital video recorder (DVR/PVR), DVD player, TV and audio amplifier. Several of these remotes may need to be used sequentially but, as there are no accepted interface guidelines, the process is increasingly cumbersome.
Many specialists, including Jakob Nielsen, a renowned usability specialist, and Robert Adler, the inventor of the modern remote, note how confusing, unwieldy and frustrating the multiplying remotes have become. Because of this proliferation of remote controls, universal remote controls that manage multiple devices are becoming increasingly popular.
2.3 REVIEW OF DIFFERENT TYPES OF REMOTE CONTROL CAR
According to different classification of motivation, remote controlled car classified as below:
1. Oil move RC car: Oil move remote control model car is powered by a fuel engine, it also can be divided into classified according to the type of fuel. Fuel powered engine has the advantage of powerful, it has high degree of onomatopoeia vehicle model simulation, and can give players a real feel. The advantages is large fuel. If there is leakage, the maintenance will be very troublesome. In addition, since the fuel is added to increase the engine power output compounds that are corrosive, so vehicles need to do careful corrosion protection, maintenance cost is not small.
2. Electric remote control car: Electric remote control car is primarily provided power by an electric motor. Due to powered by a battery, it has the higher the overall operating efficiency and excellent acceleration performance of vehicles. Because of Clean Energy, the vehicle maintenance is very convenient, just pay attention to the maintenance of transmission parts. But because the electric motor remote control car need high requirements of motor performance and battery performance, so the motor and battery  consumption is very high in the beginning, coupled with the electronic speed control, remote equipment costs. If you want to run an electric model cars, you will be basically going to spend over 2000, which is one of reason to make electric remote control model car restrictions. According to the remote control car driver type and shape classification
3. SUV: SUV can be seen as a flat road car variant, the chassis is also a flat shape. But diameter of tires is much larger, suspension travel has also increased, which is mainly to increase the performance of the vehicle through performance. At the same time to increase vehicle power, SUV also need to put forward higher requirements in vehicle steering or other aspects of the vehicle on-board electronic systems, such as the need for greater torque servo steering gear to provide powerful steering torque, etc.. The advantages of SUV is that to retains the high-speed performance and increase through performance. That is a relatively funny remote control car.
4. Monster Truck: Do not think that big wheels can be called monster truck. Monster truck is relatively flat road cars and SUV, it has its own unique characteristics. In addition to large wheels, truck biggest feature is hardly a vehicle chassis, to support vehicles parts transmission and axle systems are generally appeared in the form of frames and side plates, as if all the parts are ” hanging” on the frame. The benefits is to improve the off-road performance. The bottom of the car can be made arch to meet the rugged road, so the car has high playability. According to the different speeds, it can be graded, ordinary monster and climb monster truck. The climb monster truck is mainly designed to climb the rugged road, a huge vehicle torque, but in order to meet the torque and stability, the speed will be very slow. vehicle work requirement is very high, the price does not poor.
5. Flat road car: Flat road vehicles are concerned for RVs and cars, because of its low chassis, chassis plate-like, vehicles through poor performance, but the straight line stability and acceleration are the most superior. Two -wheel-drive flat road car is mainly used for racing, flat road four-wheel drive sports car for racing, drift race, etc.

CHAPTER THREE

METHODOLOGY
3.1 INTRODUCTION
In this project we are designing an RF remote control. For that we are using an ASK transmitter receiver module. Microcontroller is avoided in the circuit to make it cost effective. ASK module is used as the remote transmitter, two IC’s HT12E and HT12D is used for Encoding and Decoding. Circuit diagram and circuit explanation given below will help the reader to understand how a remote control car.
3.2 BLOCK DIAGRAM OF REMOTE CONTROL CAR
Before carrying out any project, the block diagram must be drawn and fully understood. Block diagram gives a pictorial understanding of any work. The block diagram of the system is as below:

Block diagram of remote control car

3.3 BLOCK DESCRIPTION
Transmitter Section:
Controlling Switches: Four button switches are used in the remote control to move the car backward, forward, left and right.
HT12E Encoder IC: It is a 212 series encoder IC used for wireless communication applications. It is mainly used to convert 12 bit parallel data (8 address bits and 4 data bits) to serial out so that it can be transmitted using a transmitter Module.
RF Tx Module: 434 MHz ASK transmitter module for transmission. It is capable of providing a data rate of about 8kbps.
Battery: 3V button cell is used to power the remote.
Receiver Section:
RF Rx Module: A high sensitivity 434 MHz ASK Receiver module for receiving the data from remote control.
HT12D Decoder IC: It is a 1212 series decoder IC used for wireless communication applications. It converts the serial input to parallel out.
Motor Driver: L293D motor driver is used to drive two motors. L293D provides bidirectional drive current up to 600mA at voltages from 4.5V to 36V.
Motors: Here two BO motors are used which are driven by the motor driver L293D and both of them are connected to robotic wheels to move the car.
Battery: Receiver section need more power than the remote control circuit. So 9V/12V battery is required to power the circuit.
3.4 ELECTRONIC COMPONENTS USED
Only basic electronic components were used here for the project. All datasheets and link to buy the components online are provided below:
Resistor:
1K Resistor: 8
Semiconductors:
HT12E Encoder IC: 1
HT12D Decoder IC: 1
Modules:
ASK RF Transmitter: 1
ASK RF Receiver: 1
L293D Motor Driver: 1    
Miscellaneous:
3V Button Cell with holder (Remote): 1
9V/12V Battery with holder (Receiver/Car): 1         
Button Switch: 4
BO Motor: 2
Robotic Wheels: 4
3.5 CIRCUIT DESIGN OF REMOTE CONTROL CAR
 The circuit diagram of the device is as below:

Rc car circuit diagram with remote control

RC car circuit diagram with remote transmitter
Circuit design of this remote control car is simple and is of low cost as we are not using a microcontroller in it. Main components are two communication ICs (HT12D and HT12E) and an ASK RF transmitter receiver module.
RC car circuit diagram with remote transmitter is designed in a compact way to make it as small as possible. Remote uses four button switches (S1, S2, S3, and S4) to control the toy. Digital data’s from the switches are encoded by the HT12E encoder IC and are transmitted to the receiver through ASK RF Module. When we press these switches, 4 data bits and 8 address bits are serially encoded and output through the pin “DOUT” is given to the 434 MHz Transmitter.  Circuit is so simple due to the simple coupling of ASK module with HT12E and HT12D pair. Remote control is power by a 3V button cell.          
Receiver section receives the signal with the help of 434 MHz ASK module and provides it to the decoder IC. “DIN” pin of HT12D gets the data from RF module and checks it three times before decoding. And if received address data matches with the encoder address data, then IC will decode the data bits and provides it directly to L293D motor driver. This driver is used to control the motors forward and backward according to the received signal. An LED is connected to the valid transmit pin of Decoder IC to indicate a valid transmission. 
Left Motor Direction
Right Motor Direction
Direction of Car

CHAPTER FOUR

4.0 RESULT ANALYSIS
4.1 CONSTRUCTION PROCEDURE
In building this project, the following procedures were properly considered,
I. Purposing of the entire materials / Components needed
ii. Resistance check of the components bought with the help of ohmmeter before making the necessary connection with the components
iii. Drafting out a schematic diagram or how to arrange the materials / components.
iv. Testing the completed system to see if the design works and
v. Finally, implementation of design of the project.
Having procured all the materials, I processed into the arrangement of the components into the Vero board but we could not laid the ics directly on the bread board because the heat soldering iron emits while soldering, proper soldering of the components then followed. The components were all soldered into the board after which it was correctly confirmed done.
4.2 ASSEMBLING OF SECTIONS
Having provided the casing and having finished the construction of the sections of this system, the assembling into the casing followed. The sections were properly laid out and assembled into the casing where the general coupling and linkages into the peripheral devices took place.
4.3 MOUNTING PROCEDURE
The transformer was bolted directly to the bottom of the case. This was followed by mounting of the power section of the circuit board. A gap was made between one mounting and the successive ones. This is necessary to avoid overcrowding. The vero board is also mounted at the upper side of the case. The resistors, transistors, and other components used were mounted on the vero board. All the accessories were highly fixed to avoid slack that may result in the process of operations
4.4 TESTING
After implementing the circuit on a project board, the different sections of the complete system were tested to ensure that they were in good operating condition. The continuity test carried out is to ensure that the circuit or components are properly linked together. This test was carried out before power was supplied to the circuit. Finally, after troubleshooting has been done on the whole circuit, power was supplied to the circuit. Visual troubleshooting was also carried out at this stage to ensure that the components do not burn out.
4.5 RESULT
The results obtained during the construction states after necessary troubleshooting were satisfactory. The system was able to respond to its operation.
4.6 ECONOMIC OF THE PROJECT
Although this project has not been given due recognition by the authority concerned, whenever this equipment finds its use the case is relatively cheap with a good efficiency and improves on its reliability. Due attention will be given to the viability of this project reliability maintainability and also the evaluation.
4.7 RELIABILITY
In the design of the remote control motor car with bidirectional rotation, reliability is taken into consideration to improve on the system performance. Here the concept of reliability has been associated, in a qualitative way with good design endurance consistence quality and dependability in recent years however, the much greater complexity of the line selector and the seriousness of a failure in the system have made it necessary to attempt not only to improve the reliability of the equipment but also to assesses it in qualitative terms.
In order to appreciate some of the difficulties which are involved in the designed of this project, imagine a discussion concerning the relative merits of remote control motor car in the first place the specifications of the picture quality and staying. The discussion may then turn to the likelihood of faults developing in the sets. This is important not only because of the annoyance caused to the viewer by a failure but pay a higher initial cost for an automatic change over switch in return for an assurance that the extra cost will mean smaller maintenance costs. Therefore, from this little explanation, “Reliability can be defined as the characteristics of a component or of a system which may be expressed by the probability that it will perform a required function under started conditions for a specified period of time.
4.8 MAINTAINABILITY
In this design and construction of this project (remote control motor car), it is usually very important to note that maintainability is another area or aspect taken into consideration since high initial or production cost will lead to a low maintenance cost. The remote control motor car has a high input output-performance, but relatively cheap, easy and low maintenance cost.
Therefore maintainability of the probability that a device will be restored to operational effectiveness within a given period of time when the maintenance action as performance in accordance with prescribed procedures”.
4.9 PROJECT EVALUATION
Considering the cost of this project one must note that fact that it is not mass production. As such to single handedly manufacture it without any industrial aided production machine will in no doubt in our much expenses, the initial market survey did not prove successful due to irregular price of item such as those used in this project.
4.10 BILL OF ENGINEERING MEASUREMENTS AND EVALUATION
The expenditure made in purchasing all the components / materials and quantity used in building this project is tabulated as show below.

CHAPTER FIVE

5.1 CONCLUSION
In this work, remote controlled motor car was implemented. The proposed system was built and a satisfactory result was achieved. Controller executes the load to rotate “FORWARD” and “REVERSE” direction depending upon the input we are giving the virtual terminal via the remote.

5.2 RECOMMENDATIONS
The device has been designed, tested and system was able to respond to its operation. This work was built with quality wiring and contains many connections, I recommend that if failure occur, it should be troubleshoot by a qualify personnel along with the circuits diagram.
This project was built for Educational purposes. If one wants to use it for industrial or home applications, I recommend that a hook should be attached to the casing that would allow fixing the system on the wall.
Working on this topic as my project is a good idea and it comes at the right time. I am suggesting that this particular topic should also be given to other students both in higher and lower class.

REFERENCES

1. Calculate the disruptive critical voltage for a three phase line with conductor of radius 1cm and spaced symmetrically, 4m apart

Vc = (3 × 10⁶)/√2 • r × inD/r

where D is the spacing Conductor

and r is the radius of each conductor

D = 4m, r = 1cm ≈ 0.01m

Vo = (3 × 10⁶)/√2 • 0.01 × in(4/0.01)

30,000/√2in400 = 21213.2×5.99

Vo = 127067.07v

2. State three (3) characteristics of fuse element
I. Low melting point e.g tin
II. High conductivity e.g copper
C. Low cost e.g lead

3. Define circuit breaker and state four types of circuit breaker
   Circuit breaker is a piece of equipment which can make or break a circuit manually or by remote control under normal condition
   B. State four types of circuit breaker
   I. Oil circuit breaker
   B. Gas circuit breaker
   III. Miniature circuit breaker
   IV. Air circuit breaker

C. State four (4) differences between fuse and circuit breaker

Fuse only work in one time and the element will be replaced
Circuit breaker work over and over again

Fuse time operation is about 0.02secs
Circuit breaker time operation is about 0.5secs

Fuse element can be tempered with when replacing
Circuit breaker can’t be tempered with

Fuse element are always replaced after operation
Circuit breaker don’t need replacement

4. List four types of insulators and sketch any one(1)
   1) Pin type insulator
   2) Suspension type insulator
   3) shackle insulator

Write short note on insulating material
Insulating materials are the material which do not allow electric energy to pass through them. They’re also used on electric poles for supporting and separating the conductor on the pole.
Examples of insulating material
I. Dry wood
II. Glass
III. Porcelain

Explain the difference between feeders, distributor and service mains
I. Feeder: is a device that serve as a protection for the transformer and distribution line.
II. Distribution mains: This is the transmission line that comes out of the transformer usually on low tension poles and carry a voltage between 220v – 414v
III. Service mains: This is the mains which is used to tap from the distribution mains to the end users.

5. Define protective relay and draw a typical relay circuit
   PROTECTIVE RELAY: is a system used in protecting an electric circuit

B) List and briefly explain four (4) requirement for power system protection.
I. Reliable, II. Stable, III. It must be timely, IV. It must be selective
I. Reliable: The protection system must provide it function when required to avoid damage of equipment, life and property
II. Stable: The protection system must not react to fault in neighbouring zone and shall not react to non fault situation
III. It must be timely: The rate at which protecting system will react to fault must be fast as possible in other to stabilise the overall power system and to reduce the damage of life and property
IV. It must be selective: only the affected point of the power system will be disconnected
C) State the purpose of protection system
I. To protect equipment
II. To protect against overload
III. To improve system stability
IV. To restore number of direction
V. To protect life and property
VI. To separate faulty section from power supply
D) List four (4) types of protection by object
I. Line protection
II. Transformer protection
III. Generator protection
IV. Earth protection

What is receptacle and Block diagram in Electrical graphics

What is receptacle in electrical graphics: Receptacle is an opening of series of opening connected to a wired power source that is supposed to power electrical components and equipment.
BLOCK DIAGRAM: Is a kind of electrical drawing that represent the principle components of a complex system in the form of block interconnected by lines that represent their relation. Block diagram is a diagram of system in which the principle parts or functions are represented by blocks connected by line that show the relationship on the blocks.

What’s relay and DPDT

(I)RELAY: A relay is an electrical operated switch. For example a 9v battery circuit connected to the coil, can switch 230v A.C mains circuit.

A Relay: is an electrical operated switch. It consists of a set of input terminals for a single or multiple control signal and a set of operating contact terminals. The switch may have any number of contact terminals. The switch may have any number of contacts in multiple forms. Such as Make contact, break contact or the combination of the two.What is Graphics symbols: A graphic symbol is a visually perceptible figure with a particular meaning used to transmit information independently of language.

What is a TRANSFORMER

Give short definition of the following; resistor, transistor, capacitor, diode, wire, cell and motor

1. Resistor : it is a device that obstruct the flow of electricity passing through a conductor. For example to limit a current passing through a LED, a resistor is used with capacitor in timing circuit.
2. Transistor: Is a device that aids in amplifying current
3. Capacitor: this are device that stores charge
4. Diode: This is a sensitive electronic components which allows current to pass in only one direction. It has two lead namely cathode and anode.
5. Wire: it serves as an entrance to pass electricity easily from one place to another.
6. Cell: it supply electrical energy
7. Motor: A transistor which convert electrical energy to kinetic energy

A series circuit having R= 40 ohm, and inductance of 0.3H suddenly connected across a 150V supply through a switch. Find;

I. The rate of change of current after closing the switch

II. The steady state value of the current.

III. The the rate of change of current I(t) = V/R – V/R . 1.

III. The value of current after 7 milliseconds

IV. The time for current to attain half it’s final value

Solutions

R = 40 ohm, V = 150V, L = 0.3H

The rate of change of current I(t) = V/R – V/R . e–¹³³·³t

1. Rate of change of current after closing the switch

di(t)/ d(t), when t = 0

di(t)/ d(t) = 3.75 – 3.75e–¹³³·³t

Then differentiate,

0 – 3.75×-133.3e–¹³³·³<⁰>

0 – 499.88e⁰

0 – 499.88 × 1

0 – 499.88

= 499.88 A/S (Amperes per second)

2. The steady state value of the current

Base current (Ib) = V/R = 150/40

= 3.75A

3. The value of current after 7 milliseconds

The rate of change of current (It) = 3.75 – 3.75e–¹³³·³t

when t = 0.007seconds

The rate of change of current (It) = 3.75 – 3.75e–¹³³·³×⁰·⁰⁰⁷ (It) = 3.75 – 3.75e–⁰·⁹³

(It) = 3.75 – 3.75e–⁰·⁹³NOTE: e–⁰·⁹³ Means exponential of 0.93 (how to get it, press (in) in your calculator with 0.93. You’ll have 0.117)

(It) = 3.75 – 3.75(0.117)

(It) = 3.75 – 0.44

(It) = 3.31A

4.The time for current to attain half its final value

Base current (Ib) = 3.75A,

Ib/2 » 3.75/2 » 1.875A

1.875 = 3.75-3.75e–¹³³·³t

Collect like terms

3.75e–¹³³·³t = 3.75-1.875

3.75e–¹³³·³t = 1.875

e–¹³³·³t = 1.875/3.75

e–¹³³·³t = 0.5

-133.3t = in(0.5)

t = [-1/133.3 ] in(0.5)

t = -7.5 × 10–³ × -0.69

t = 5.2 × 10–³ seconds » 5.2milliSeconds. [final answer]

WHAT’S THE FUNCTION OF FOCUS ADJUSTMENT AND ELECTROSTATIC FOCUSING IN MONOCHROME TV

THE BLOCK DIAGRAM OF A TYPICAL MONOCHROME RECEIVER.

1) FOCUS ADJUSTMENT: The focus adjustment is the electron beam. The electron beam must be focused to small ports/spot light on the screen usually focus is sharp on the center area of a tube.
FUNCTION: Older picture used in magnetic focusing with a focused signal on the neck of the tube behind the deflection yoke.

2) ELECTROSTATIC FOCUSING: Is omitted from a cathode tends to diverge because they repel each other. However the electron can be forced to converge to a point by an electric or to a magnetic field. So the voltage focused in the beam to a spot is called a crossed point beyond the control grid.

1 PIN TYPE INSULATOR: Are made in piece up to 25KV and above for up to 50KV only. You can add up the voltage by adding one more piece, they become uneconomical for higher voltage.

2. SUSPENSION TYPE INSULATOR: Are made in form of disc and a number of them used in a flexible string for the voltage range desires with the conductor being attached to the lower end for 400KV lines, 19 discs of overall length 3.84m are used.

3 STRAIN TYPE INSULATOR: Are obtained often a string of suspension insulator is used in a horizontal position. They are mainly used in line terminal and crossed end roads.

An autotransformer is supplied at 240V. If the secondary is tapped to give 60V with a load current of 12A, calculate the other two circuit currents and show the direction of current and voltages (5 marks)

Solution
V1 = 240V, V2 = 60V, i1 = 12A
(I)THE OTHER TWO CIRCUIT CURRENTS
From transformer ratio K = V1/V2 = i2/i1
240/60 = 12/i1
i1 = 60 × 12/ 240
i1 = 3A
Recall,
i1 = i2 + i3, i3 = [i2 – i1]i3 = 12-3
i3 = 9A

QUESTION ONE

The four parameters that determine the performance of a transmission line is conductance, resistance, inductance and capacitance.

1. RESISTANCE: Resistance is stated in ohms per meter length of a line and its represent the imperfection of a line. In other words, it obstruct or resist the flow of  current in a circuit. It’s measured in ohms [Ω]
2. CAPACITANCE: It is the ratio of the charge on one plate of a capacitor to the voltage difference between the two plates. Its measured in farads [F]. Or it can be define as the ability of a capacitor to store charge.

1. INDUCTANCE: Is a property in which an inductor, exhibit an opposition to the current flowing through it. Or it can be define as the process in which an E.M.F is produce to oppose the current flowing through it. It’s measured in henry [H]
2. CONDUCTANCE:  It is an ability of an element to conduct electric current, it is measured in siemens[S]

2011/2012

list five (3) advantages and three (3) disadvantages of a hydro power plant.

Answers
(1) Renewable: hydro-electric energy is renewable, that means hydro-electric energy can be generated again after been used up.

However, there’s only a limited number of suitable reservoirs where hydro-electric power plants can be built and even less places where such projects are profitable.
Pollution free: it is clean and good. There is no pollution at all.

(2) Reliable: it is very reliable because it has sufficient energy. A house, shop or industry can use once there is sufficient water in the dam.

(3) Flexible: hydro-electric power can be tapped or taken to different households or without difficulty and adjusting water flow and output of electricity is easy.
Safe: compared to among others, fossil fuel and nuclear energy, hydro-electricity is much safer.

Disadvantages
(1) It involves high capital cost due to construction of dam.
(2) There is uncertainty about the availability of huge amount of water due to dependence on weather condition.
(3) Skilled and experienced hands are required to build the plant.
(4) It requires high cost of transmission lines as the plants is located in hilly areas which are far away from the consumer.

Nuclear power station

(2) There are large deposits of nuclear fuels that can ensure the continuity of electrical energy for thousands of years are available all over the world.

(3) It can be located near the load centers because it does not require large quantities of water and need not be near coal mines. And therefore, the cost of primary distribution is reduced.

(4) This type of plant is very economical for producing bulk electric power.

(5) It has low running charges as a small amount of fuel is used for producing bulk electrical power.

(6) A nuclear power requires less space as compared to any other type of power station.

(7) The amount of fuel required is small.
Disadvantages
(1) The fission by-products are generally radioactive and may cause a dangerous amount of radioactive pollution.

(2) The erection and commissioning of the plant requires greater technical know-how.

(3)The capital cost on a nuclear plant is very high as compared to other type of plants.

(4) The fuel used is cost and is difficult to renew/recover.

What is signal

Signals is a physical quantity or an electrical waveform that carries information. It can also be define as a pattern, or changes that convey information from a source to a destination. The purpose of a signal is to transmit this information timely and accurately. Signal is a physical and electrical representation of information that is used to transmit data in various communication system.

Type of signal

1. Analog signals: They are continuous waveforms that vary in time and amplitude
2. Digital signals: They are not continuous wave but are discrete in nature i.e their values are typically binary digits (bit) a “0” and a “1”

Characteristics/properties of signals

1. Amplitude: These refers to the magnitude or strength of the signals
2. Frequency: is the number of cycles or oscillation that occurs within a given time period. Measured in hertz (Hz)
3. Phase: Refers to the relative positioning or timing of a signal waveform with respect to a reference
4. Duration: Represent the length of time that a signal persist or exist.
5. Periodicity: Refers to whether a signal exhibits a repetitive pattern or not.
6. Symmetry: These describe the balance or distribution of a signal waveform
7. Bandwidth: it refers to the range of frequency that signal occupies or occupies for transmission
8. Energy and power: are measures of the total or average amount of signal energy overtime. Energy is related to the finite duration of a signal while power is the energy per unit time

Example of analog signals

1. Audio signal: In electronics, an audio signal generator is a piece of electronic test equipment that generates electrical signals in the audio frequency range. These signals are usually created using a voltage-controlled oscillator or a pulse train and then route to an amplifier before being sent to the loudspeakers, whose output makes up the desired sound.
2. Electromagnetic waves: The electromagnetic waves consist of both electric and magnetic fields. Electromagnetic waves can travel long distances in space. The electromagnetic signals are also called radio frequency (RF) waves
3. Voltage signal: a voltage signal refers to an electrical signal that varies in voltage, typically measured in volts. Voltage signals are often used to represent analog data such as sound, temperature, and light intensity

Application of analog signals ( where we can find it)

1. Analog telephone
2. AM/FM radio
3. Television broadcasting

Note: that analog signals are susceptible (likely or affected) to noise and distortion during transmission, which can degrade the quantity of the received signal.

Advantages of digital signals

1. Immunity to noise ( insusceptible)
2. Better signal quantity
3. Efficient use of bandwidth

Digital Modulation

It is the whole process of modifying a digital signal to enable it to be transmitted over a communication channel.

Digital modulation techniques

1. Amplitude shift keying (ASK): In ASK the amplitude of the common signal varied to represent digital “1_s” and “0_s“
2. Frequency shift keying (FSK): It involves shifting the frequency of the carrier signal between two or more predefine frequencies to represent different digital symbols. For example, if we have two sine waves with different frequencies but equal amplitudes, they would be indistinguishable on an oscilloscope unless we normalized their amplitudes first. If you multiply each frequency by its corresponding normalized amplitude measurement, you can use frequency as an independent variable.
3. Phase shift keying (PSK): It changes the phase of the carrier signals to represents digital symbols ( 0⁰, 90⁰, 180⁰, 290⁰ )
4. Quadrature amplitude modulation (QAM): Is a complex modulation scheme that combines amplitude and phase modulation. (QAM represents digital data in varying both the amplitude and phase of the carrier)
5. Quadrature phase shift keying (QPSK): is a modulation scheme that allows one symbol to transfer two bits of data. There are four possible two-bit numbers (00, 01, 10, 11), and consequently we need four phase offsets. Again, we want maximum separation between the phase options, which in this case is 90°
6. Orthogonal frequency division multiplexing (OFDM): Orthogonal frequency division multiplexing (OFDM) takes a digital information signal with bit rate R_b, maps n-bit words on to M = 2ⁿ symbols (each symbol being a complex number representing the amplitude and phase of an M-ary modulation scheme), splits the resulting symbol stream (rate R_s = R_b/n) into N parallel streams (each with rate ROFDM = R_s/N) and modulates each stream onto one of N different carriers [12]. The N frequencies chosen for the carriers are such that the carriers are mutually orthogonal over one OFDM symbol period, T_OFDM = 1/R_OFDM, allowing independent recovery of each parallel information stream.

Digital modulation principle

1. Pulse amplitude modulation (PAM): Converts a discrete time signal into a variable amplitude continuous time signal that is good for high-speed wired communication system.
2. Pulse position modulation (PPM): Is a modulation method that only makes every pulse in the carrier pulse sequence change within time but without changing shape and amplitude of pulse signal.
3. Pulse Code modulation (PCM): is a digital scheme for transmitting analog data. It converts an analog signal into digital form. Using PCM, it is possible to digitize all forms of analog data, including full-motion video, voice, music, telemetry, etc.
4. Pulse Width modulation (PWM): is a modulation technique that generates variable-width pulses to represent the amplitude of an analog input signal. The output switching transistor is on more of the time for a high-amplitude signal and off more of the time for a low-amplitude signal.

This entails a quick Question & Answer summary of what Drafting and design course is all about in electrical engineering. As a student who’s interested in Drafting and design course, it’s advisable you go through this.

1. List three(3) types of connection diagram in an electrical design

• Block diagram
• Wiring diagram
• Schematic diagram

Write short note on each types of connection diagram

• Block diagram: is a symbolic representation of a working process, production line or even it can be used to represent a system of government activities.
• Schematic diagram: it is a standard name used for a circuit diagram. It can be defined as a diagram that utilizes a circuit symbol to show the interconnection and function of a component that makes up of a circuit diagram of a system.
• A wiring diagram: shows the relative layout of the components and the wire connections between them. This type of diagram shows the physical relation of all devices in the system, the conductor terminations between these devices, and are commonly used in motor control installations

B. state four(4) classification of lighting scheme

• Direct lighting scheme
• Indirect lighting scheme
• Semi-direct lighting scheme
• Semi-indirect lighting scheme

• Direct lighting schemes: By this method most of the lighting scheme is made available on the working surface and very few percent is wasted. Light shining onto an object is called direct lighting. It determines the color and quantity of light that reaches a surface from a light source, but ignores all light that may arrive at the surface from any other sources, such as after reflection or refraction.
• Indirect lighting scheme: The light does not reach the working surface directly.  Uses one or more fixtures to aim light onto the ceiling and upper walls, which act as reflectors and distribute the light evenly throughout the room. Indirect lighting is a form of ambient lighting.
• Semi-direct lighting scheme: In this scheme about 60 to 90% of total light flux is made to fall on the working surface and 10 to 40% is allowed to fall on the ceilings and walls. This is achieved by providing semi-direct reflectors. Such a scheme is best suited to rooms having bigger height
• Semi-indirect lighting scheme: In this system 60 to 90% of the total light flux is diverted to fall on the ceiling from where the light is directed on the working surface by diffused reflection. Only 30 to 40% flux reaches the working surface.

C. Write short notes on each of the following; cosine law, inverse square law, maintenance factor and diversity factor.

• Cosine law: the illumination on the surface is proportional to the cosine of the angle X between the direction of the incident light and the normal to the surface.
• Inverse square law: this illumination at a point for the surface produced by light from the point of source was inversely to the square of the point of source.
• Maintenance factor: it refers to the loss of light that occurs over time and is also known as loss factor. During the operating time of light sources, it can be seen as slight decrease of light output. in other words it is called lumen
• Diversity factor: this is the ratio of the sum of individual demand of the various sub-division of the system to the maximum demand of the whole system under consideration.

2. Enumerate the difference between switch gear and distribution switch board

Switch gear

• Switch gears protect equipment from electrical hazards or failure due to short circuit.
• Switch gear finds their use in powering transformers lines, generators and power networks.
• Switch gears is designed to handle voltages that can reach 350KV.
• Switch gears come with automatic features and come with manual control during emergency.
• Switch gear has switching device that are required for low to medium-voltage circuits.

Switch board

• They are designed to handle lower voltages that are generally less than 60 volts
• Switch boards don’t have any automatic features and are placed to display the amount of power consumed by individual circuits.
• They consists of panel where switches, buses and electrical control devices have been mounted on the front or back end
• They are only used to distribute power to multiple sources and transmit them to individual loads, transformers, panel boards and control equipment.
• They have fixed mount circuit breakers that are connected directly to bus bar.

B. State four(4) factors to be considered when selecting a consumer unit for an installation.

• Number of circuits
• Type of circuits
• Brand and model
• Price

C. Explain briefly the difference between domestic premises and non-domestic premises and state the types of supplies which are taken to each of the premises stated above

Domestic premises are residential wiring that run through walls in a single phase design and it uses less voltage due to lower electrical load.

Non-domestic premises are industrial wiring that uses a three-phase design to create higher output to power higher voltage equipment and multiple systems.

Note: Domestic premises make use of 230/240V while non-domestic premises make use of 11/33KV

3. Explain briefly the term stroboscopic effect on rotating electrical equipment.

Stroboscopic effect is the phenomenon which makes moving objects like fan blades to appear to be stand still and a wave of the hand to appear as if it occured in a series of jump.

State two(2) methods to be adopted so as to reduce stroboscopic effect

1. Using three lambs on the separate phase of 3-phase supply: when three(3) phase supply is used in the industry the adjacent fluorescent lamps should be fed with different phases so that the zero crossing of the two lambs will not be the same.
2. Reducing the level of TLMs: design of lighting equipment to reduce the TLMs of the light sources is typically a trade off for other product properties and generally increases cost and size, shortens lifetime or lower energy efficiency.

What are the different special purpose of transformer?

You can use transformer as;

1. Regulating transformers
2. Converter transformer
3. Rectifier transformer
4. Mining transformer
5. Welding transformer

What is reactor?

Reactors are equipment of transformer family. Reactors are used in the power system(network) for current limiting and for compensation of reactive power.

Types of reactors

1. Series reactor: are necessary for limiting short-circuit currents, for limiting rush currents while switching-in for limiting current surges with fluctuating loads, for smoothing the current wavesform, etc.
2. Shunt reactor: are necessary for shunt harmonic filter and for providing reactive power compensation for long AC lines.

What is transformer?

Transformer is a static electrical equipment which transformer are electrical power from one voltage to another voltage at some frequency by electromagnetic induction. The transformer design, manufacturing and testing techniques have advanced with following objectives;

• High efficiency
• Low material cost, smaller size
• High reliability, long life, low maintenance.
• Low noise
• To conform to relevant specifications.

Important advances in power transformer technologies includes;

1. Improved magnetic materials for core

• Lower losses
• Reduced size of core

2. Improved method of construction of core

• Elimination of core bolts
• Use of mired joint between laminations of leg and yoke.

3. Improved conductors and conductor insulators: multiple wire transposed conductors are now used, thereby the eddy current losses and skin effects are reduced.

4. Reduction in Noise: use of superior magnetic sheet steel, improved method construction of core and tank.

5. Improved design of windings and insulating system: The distribution of electrical stresses between winding and core, windings, turns of a winding, coils of a winding depends on electromagnetic phenomena,.

Types of transformer

1. Core type transformer: A transformer on which the windings surrounded the limbs of the core.
2. Shell type transformer: A transformer in which the core surrounds major portion of the windings.

Principle of operation of transformer

A transformer has two or more separate winding placed on a common magnetic core. It works on induction principle. The primary winding is supplied with alternating current of supply frequency. Thereby alternating magnetic flux of the same frequency is produced in the magnetic core.

What is testing in transformer?

Testing: is to ensure good health of transformer and trouble-free service

Kinds of test on a transformer

1. Acceptance test: validates that your product is built and operating following design specifications and regulations. For transformers, it’s the process of testing to confirm that it meets all elements of the international standard
2. Type test: type test prove the capabilities and guaranteed ratings
3. Routine test: are conducted to verify that the manufactured and assembling are satisfactory
4. Special test: are conducted in testing laboratory or at site to investigate certain phenomena.
5. Site test: are carried out after complete installation to confirm that there are no transit damages and installation is satisfactory.
6. Quality checks test: these are conducted on components, sub-assembling and complete assembly to confirm that the quality is satisfactory and there are no material/manufacturing defects.

What is a substation

A substation is an assemblage of electrical apparatus. Transformer are necessary in a sub-station for stepping-up and stepping-down of voltage. Besides transformers, substations has several other electrical equipment’s including bus-bars, circuit breaker, isolators, surge arrestors, etc.

1. Busbars: Incoming and outgoing circuits connected to bus-bars.
2. Circuit breakers: Automatic switching during normal or abnormal conditions.
3. Insulators: Disconnection under no-load condition for safety, isolation and maintenance
4. Earthing switch: To discharge the voltage on dead lines to earth.
5. Current transformer: To step-down current for measurement, control and protection.

CHAPTER ONE

INTRODUCTION

The off-grid system term states the system not relating to the gird facility. Primarily, the system which is not connected to the main electrical grid is term as off-grid PV system . Off-grid system also called standalone system or mini grid which can generate the power and run the appliances by itself. Off-grid systems are suitable for the electrification of small community. Off-grid electrification system is viable for the remote areas in the countries where they do have little or no access to the electricity because of the distinct living and spread population in the vast area. The off-grid system refers to the support that would be adequate for a living without depending on the grid or other system. Electrical energy in the off-gird system produced through the Solar photovoltaic panels needs to be stored or saved because requirement from the load can be different from the solar panel output, battery bank is also used for the purpose generally.

1.1 Background of study

Energy systems often include Renewables Energy Systems (RES). RES play an important role from technical, economic, social and environmental point of view. The high cost of the fuel used in systems based totally on diesel generators (gensets) has led to the development of hybrid energy systems. Hybrid energy systems are the combination of two or more energy sources, from Renewable Energy Technologies (RETs) and from conventional technologies, with an energy storage and power conditioning system. The use of RES would reduce the fuel consumption as well as the polluted emission of a 100% diesel plant. The initial investment will be higher in a hybrid energy system, but the use of fuel and consequently its cost will be reduced.

1.2 Statement of the problem

About 1.3 billion people worldwide have no access to electricity. Around 20 % of the total population, most of them located in rural or isolated areas have little or no access to main grid. A good development of Mini Grid systems, apart from offering reliable electricity, could also improve the economy of these areas. On the other hand, climate change implies finding new ways to obtain energy and protect the environment, renewable energy systems are escalating fast, and can lead to fight carbondioxide(CO2) emissions in a high percentage. Three important fields to consider in this study will be technical, economic and social aspects, which have to be taken into account when choosing a Mini off-Grid system implementation. Regarding the technological dimension, significant advances can be observed with these kinds of technologies. Secondly, there is a need for an affordable operation and durable system installation. Thirdly, with respect to the social dimension, a lack of communication exists between foreign companies that install the components taking part in mini-grid systems, and the locals that live in rural or isolated areas and own the land. In addition, there are some constraints when evaluating the success of the whole system installation and its performance. For instance, referring to PV and wind turbines, it is known that they do not always work at their maximum production level, since it will always depend on the daily sun radiation and wind speed. This situation could lead, in some cases, to an overuse of the diesel generator implying greater economic expenses and higher emissions. Moreover, another disadvantage related to the installation process is the difficulties that can be found in reaching isolated areas due to the existence of poor access, for example, for transportation. In summary, the current study is relevant principally to provide these communities and areas with reliable electrification; consequently, implying an improvement in their lifestyle and economy. Therefore, this document tries to explore the crucially important position of households in Mini off-Grid systems in order to achieve a better understanding and a more encompassing policy debate while taking into account the proper and most efficient use of natural resources.

1.3 Aim and Objectives of the Research:

The usage of solar energy is increasing day by day both in terms of demand and usage. Our aim is to provide the most useful solar solution while maintaining the novelty. So, the construction of a mini off-grid solar home system. Futhermore, An off grid system with DC load along battery bank. The off-grid application is considered because the system is to be independent of the grid so that it can be used at any time.
The objective of this research is to provide a better understanding of the different kind of impacts the use of off-grid solar systems has upon the livelihoods of households

1.4 Contribution to knowledge

The construction of a mini off grid solar system has brought about the understanding that life can be made a lot easier with the presence of a mini off grid solar system as sun is free, sustainable, clean resources we can leverage in place of convectional electricity to power our lives. Solar energy can be used to provide heat, light and other electricity-dependent needs in homes

1.5 limitation/scope of the project

Some of the limitations of an off grid mini home solar system include;

• They are more costly
• batteries are required to deliver electricity consistently throughout the day and night
• it could require a lifestyle change to reduce energy consumption
• surplus energy production
• cannot rely on the grid at night or on cloudy days
• batteries require maintenance, have a relatively short lifespan and degrade rapidly

CHAPTEER TWO
2.0 LITERATURE REVIEW

2.1 Brief outline of the project

2.2 Historical background of the project

The term off grid first appeared in the mid nineties, highlighted by the environmental nick Rosen in the launch of an ecological motivated website www.offgrid,net and featured more recently in his book how to live off grid (Doubleday 2007)
The history of solar energy
Thinking of solar energy in the 21st century,a smart system of powering our homes with the light from the sun and solar panels. While solar panel technology is relatively new, dating back about 50 years, the use of suns energy to sustain livelihoods in fact began a number of centuries ago.
History with the sun has a far dating and fascinating history, documented from as far as the 7th century B.C . Societies, throughout time, have been using the suns energy in intelligent ways to facilitate their lives. From the discovery of fire to the vast commercialization of solar power and domestic usage in todays world.
The solar energy we have known to come and love as a renewable form of energy, has inspired some of the greatest changes in recent times . Below is the summarization of the solar energy breakthroughs from the 16th century to the present day
Ancient uses of solar energy
Early uses of the sun focused on harnessing the sun’s energy for use as a heat source. Dating back to the Ancient Egyptian civilizations, buildings were designed in ways that maximized light entry and warmth.
From the 3rd Century B.C., the Ancient Greeks and Romans were using sunlight to create fire torches. Proving particularly handy for sacred and religious ceremonies.

The 16th-17th century: Development of the first solar cell
Fast forward to the 16th century, the first solar cell was designed by Swiss Scientist Horace-Benedict de Saussure in 1767.
Seventy-two years later, further innovation and progress in the evolution of solar energy was made. At just 19 years old, French scientist Edmond Becqurel discovered the Photovoltaic Effect: voltage and electric current in materials can be generated upon exposure to light.
By 1870, another milestone was reached where the discovery that light could be turned into electricity without heat is made.
Moving onto the 1890s, the first commercial solar heat pump was patented.
By the end of the 17th century, American inventor Charles Fritz created the first working selenium solar cell (in today’s era, silicon is used in cells for solar panels).
Up until this point, the contribution and experimental discoveries of various inventors and scientists had led up to the creation of the modern solar photovoltaic (PV) panel.

Early 20th Century: The modenization of solar energy
1905 was the year a young Albert Einstein (26 years old at the time) published his work titled “On a Heuristic Viewpoint Concerning the Production and Transformation of Light.” Where he studied what became known as the photoelectric effect.
1917 Einstein gave a theoretical foundation to photovoltaics by introducing the notion that lights as packets carry electromagnetic force.
By 1954, scientists at Bell Laboratories developed the first practical photovoltaic cell.
By the mid 1950s the first solar-powered telephone call was made. Illustrating the further development and reliability in solar energy being recognised.
A year later in 1956, the first solar powered radio was introduced by General Electric. The radio was able to function in the day and night.
Just a few years later, the US experimented with the application of solar PV cells on Earth orbiting satellites. Since then and up to the present day, solar power is the accepted energy source for space applications!
By 1958 a spacecraft called Vanguard I became the first to be powered by solar panels.
In London 1960, the first solar car was introduced, with a solar-panel roof and a 72-volt battery.
1982 was when the first large-scale solar farm was built near Hesperia, California.
Developments in solar continued throughout the 1990s, and emerging global economies began to grow their share in renewables (especially wind and solar PV) during this time.
The 2000s: Solar energy goes commercial
From the 2000s, solar power starts to become accessible for everyone. The renewable energy sector is booming and the following decade sees ground-breaking advancements and the expansion in solar PV tech and their installations respectively.
Mandatory targets for renewable energy are now set across the EU.
We see the development of a competitive internal energy market, with renewables playing an important role.
From the 2000s to the 2010s, more capacity is added to the renewables sector than any other (and this trend is continuing!).
In 2012, the European Photovoltaic Industry Association, stated that ‘the solar PV industry installed more than 30 gigawatts worldwide which led to the cumulative global installations to be more than 100 gigawatts.’
Solar panels become more efficient, convenient and easier to access for home and business owners. As of 2018, there were more than 1 million solar PV installations.
During 2018, the UK generated 3.9% of its total electricity using solar power.
2019 saw the first offshore floating solar farm is installed in the Dutch North Sea.
By 2020 it was cheaper to build a new solar plant than it is to continue operating an existing coal plant. Showing just the extent of our reliance on solar energy.
By 2020 The International Energy Agency declared that “Solar is the new king of the electricity markets”.
And finally, 2021 and 2022 is set to see renewable energy accounting for 90% of new power capacity expansion globally.
The present day: Solar energy goes global
Today, we continue to see the expansion and use of solar powered devices, infrastructure and transport. Investments into solar parks and farms (both the small and mega) continue to take place across the globe.
The historic advancements and current position of solar place the power of this renewable resource in a promising position. In terms of the UK’s solar future, it looks particularly bright as it sets to double its solar capacity by 2030.

2.3 Theory and concept revelant to the study

2.3.2 Shade Analysis: Shading can be a problem for the solar panels as they decrease the maximum power that can be generated. Several factors contribute to this issue, the most common cause of shade on a solar panel are;

1) Shade from neighboring trees and buildings in vicinity,

2) typical cloudy weather, and

3) shade from adjacent solar panels.

While designing a solar PV system one must investigate these factors thoroughly so that maximum output can be obtained. One of the tools most commonly used is solar pathfinder which gives the direction of the sun throughout the year and how much any specific area will receive sunlight throughout the year. Apart from having this tool, it is important that the site assessment is done properly to locate the best site keeping in mind all the aspects.
Sun hours: Sun hours are important to know how much radiance will be required to generate the needed output wattage. This parameter gives us the knowledge of number of hours an area will receive maximum sunlight. With advances in technology we have this data available online and anyone can use it. We have studied the data from NREL and NASA but for our project we will be uvsing data given by NREL as it is giving information of the Sun hours to a closer proximity to Charleston. The following chart gives the required information of the Sun hours depending on different zones classified by NREL
chart 2.2 Sun hours depending on different time zones

Tilt angle: Tilt angle is the setting of the panels one needs to have to get the maximum radiance. Ideally the tilt angle is the latitude of the geographic location. It is suggested to have an adjustable panel frames as the sun hours keep changing with respect to the tilt in winters and summers. Hence for any area a specaific tilt angle is calculated to get the maximum radiance throughout the year for a fixed panel. Also, it is advised to have the panels facing the south to get the maximum afternoon sun. A couple of devices are used in the process of finding the tilt angle and the radiance that will fall upon panel at that tilt angle are inclinometer and pyrometer, respectively. An inclinometer is kept on the panel and the degrees are read to find the latitude of the area as it is perpendicular to the Sun’s radiations when it is at its highest point in the sky. Pyrometer measures the solar irradiance that will fall at a given tilt angle. It measures solar irradiance in Watts per meter Sq.
2.3.3 Battery Sizing;
PV battery system assesses various strategies from a financial perspective. The valuable existence of the battery is limited to 5,000 cycles or in the planned living time of 20 years. The maintenance of photovoltaic and rechargeable annual activities and expenditure systems is set at 1.5% per the speculative cost. Assume that the cost system for the battery and PV is comparable to their size. Following is a formula that will enable to calculate what size of battery they should have. (Leonics, n.d.) Battery Capacity (Ah) = Total Watt-hours per day used by appliances x Days of autonomy (0.85 x 0.6 x nominal battery voltage)
2.3.4 Inverter: Inverter deals with following main tasks of energy: (ALTE store, n.d.)
Convert DC from PV module to AC
Ensure that the cycle of alternating current cycles is 60 cycles
Reduce voltage variations
Ensure that the condition of the AC waveform is suitable for the application
Most system-connected inverters can be introduced externally, and most of the off-grid inverters are not weather-resistant. There are basically two types of grid intelligent Inverters: Those designed for batteries and those designed for systems without battery-connected inverter systems and give excellent void-quality strength. For matrix associations, the inverter should have a “useful-interactive” typeface, which is printed specifically for the publication name.
Grid-connected systems measure the power of extracting PV clusters rather than a bunch of prerequisite buildings. It asserts that what each power supply needs are what the matrix-related PV system can give naturally is drawn from the net. Invertors used for solar PV systems are usually based upon the total wattage of the solar panels, as the invertor will be continuously converting the power generated. The second consideration one must investigate, is the voltage level of the system. For example, if the system is designed to generate 2000 Watts at a voltage level of 12 V then the invertor selected should be rated 12V, 2000 Watts (Alternative Energy, n.d.).
2.3.5 Charge Controller: The charge controller, sometimes referred to as a photovoltaic controller or charger, is only necessary for the system which involves a battery (Wholesale Solar, n.d.). The main capacity of the charge controller is to counteract the battery spoofing. The basic function of charge controller is to monitor charging and discharging of the battery. It prevents the battery from being completely charged or discharged. This is important because over charging can lead to destruction of the battery and under charging decreases the battery life. Another important reason to use a charge controller is to prevent a reverse current flowing from battery to the system. There are two types of controllers that are widely available in the market; 1) Pulse width Modulation (PWM), 2) Maximum Power Point Tracking (MPPT) (Northern Arizon Wind and Sun, n.d.) 1. Pulse width modulation: A pulse width modulation charge controller is set match the input power of the battery irrespective of the power generated by the panels. There is an inherent loss in power observed in this type of charger. 2. Maximum Power Point Tracking (MPPT): This type of charger helps to get the optimum charging power for any given point of time and offers better efficiency that PWM. Though the MPPT charge controllers enable you to have better efficiencies and provides more power than compared to PWM for similar condition, the main cause of not opting for MPPT is price of it (Solar Guy, 2016). MPPT charge controllers are more expensive than PWM controllers. Keeping this parameter in mind, this project will be using a PWM charge controller for realizing the concept. To select the size of charge controller one must know the voltage level of the system and the maximum operating current. It is a usual practice to over size the controller for safety reasons. Proposal to Convert 7th Street Bus Stand into a Standalone PV System Bus shelters are common in every structure one can find in urban and sub-urban settings and most of them are tied to the grid to provide electricity. But most of the rural and sub-urban areas do not have this facility of having their bus shelters electrified through grid. In such place we could use the off-grid or standalone PV system which can function without the grids assistance. Eastern Illinois University has always been a leader in embracing new technologies that promotes betterment of the environment and its students. Panther shuttle bus-stops across the campus serve hundreds of the students on a day-to-day basis. Currently, all the bus stops on the campus are not connected with the existing electrical grid. Hence, taking an initiative to serve the students an also realizing a proof of concept for standalone systems the following PV system has been designed.

CHAPTER ONE

1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
With the rising need of electricity in its efficient, less toxic, consistent and cheapest form, there is need to explore every means of satisfying the aforementioned needs and solar electricity has been one of the leading ways to achieving that. Solar electricity provide consistent and steady source of solar power throughout the year. The main benefit of solar energy is that it can be easily deployed by both home and business users as it does not require a huge setup. Solar energy not only benefits individual owners, but also benefit environment as well. It is non-polluting as it does not release harmful gases like carbon dioxide, nitrogen oxide, or sulphur oxide. Solar energy requires low maintenance, does not create noise, is easy to install and can be used in remote locations. Solar electricity is one of the most widely used renewable energy source.

Solar energy is energy that comes directly from the sun. The sun is a constant natural source of heat and light, and its radiation can be converted to electricity. This source will last for at least a billion years (Royal Swedish Academy of Sciences, 2010). First photovoltaic (PV) solar panels have been designed and used mainly in space technologies, as the production costs of such panels were very high. As the time passes, the photovoltaic cells can be produced cheaper and cheaper and their efficiency is rising (Nese and Grenci, 2011). This is also a reason why they are being used much more frequently and it is not rare to see them on the rooftops any more. The future offers even bigger possibilities, as new thin plastic solar cells are being developed with prospects of cheap large scale production using printing technology (William T. et al., 2010).
Photovoltaic solar systems can be divided into two basic categories grid connected and off-grid(also stand alone or isolated) solar systems. The grid connected systems feed the electricity produced by solar panels to the grid using an inverter. When the electricity is needed during night or periods with little sunlight, the energy is taken back from grid (AlekIndra, 2011). In isolated systems, the excess electricity is usually stored in batteries during the day and batteries are used to power the appliances in times when photovoltaic panels do not produce enough energy. A photovoltaic (PV) system may be a combination of several components such as a battery system, DC/AC conversion circuits and other power conditioning devices, in addition to the solar panels themselves (Piao, Z.G. et al., 2005).
A lead-acid battery is an electrical storage device that uses a reversible chemical reaction to store energy. Using lead-acid battery charge can be stored more swiftly by grid connected system. A dc chopper converts directly from dc to dc and is also known as a dc-to-dc converter. A dc chopper circuit can be considered as dc equivalent to a transformer with a continuously variable turn ratio. Like a transformer, it can be used to step-down or step-up a dc voltage source. Here a dc-to-dc converter is used to charge the battery sufficiently. The information presenting in this body of work concentrates more on the electronic means of enhancing energy efficiency in a PV system as well as describing energy storage and power grid integration techniques. This branch of power electronics is generally called power conditioning and in the present case is used to describe the management of electrical energy to effectively charge batteries, draw maximum power from the solar panels or provide a high quality AC output.

1.2 STATEMENT OF THE PROBLEM
Today the micro-grid for solar home system has turned out to be a very promising solution for remote places of Nigeria where the grid supply has not reached yet. In this regard our conventional solar home system charge controller is asking for a solid and innovative solution to accommodate variety of solar panels with different voltage level for micro grid. So far the solar home system charge controller we have in the present market is customized for 15V panel mostly. Looking at this problem we tried to come up with a new charge controller, based on DC to DC fly-back converter which enables the system to use any voltage level solar panel and charge the same 12V battery. One of the other important features of this charge controller is that, as it allows the system to use high voltage panel like 48V, the copper loss from panel to charge controller is much smaller compared to other system. As the charge controller remains with the battery, the panel to charge controller wire loss dominates the total system loss and therefore our proposed charge controller can make the conventional solar home system more efficient and more effective.
An important aspect of the solar electricity setup is the charge controller. It is inevitable when mentioning solar electricity as it forms an integral part of the solar electricity family. A charge controller limits the rate at which electric current is added to or drawn from electric batteries. It prevents overcharging and protect against overvoltage, which can reduce battery performance or lifespan and may pose a safety risk. It may also prevent completely draining (deep discharging) a battery, or perform controlled discharges, depending on the battery technology, to protect battery life. Because the intensity of sunlight fluctuates throughout the day, the output voltage of a solar panel fluctuates as well. In addition, because of this fluctuation, a solar panel is padded with more cells to compensate for times when the intensity of sunlight is low.
The intensity from the sun fluctuates all day which increases or decreases the current and voltage entering the battery and leads to its damage and shorter life-span. This gave rise to the invention of the charge controller which regulates the voltage and current to keep the batteries from overcharging and also deals with reverse current. The Maximum Power Point Tracker (MPPT) as an advancement of the charge controller family helps to maximize the voltage from the solar array and provide stabilized voltage for the battery.

1.3 AIM AND OBJECTIVES OF THE PROJECT
1.3.1 Aim
This project is aimed at assembling a solar battery with charge controller to effectively regulate the current and voltage coming from the photovoltaic into the battery bank ensuring efficient power supply and longevity.
1.3.2 Objectives
The main aim shall be achieved by:
Constructing a working circuit diagram for the proposed charge controller
Getting the necessary components needed to realize the set project
Programming the microcontroller to track the output power of the MPPT while comparing the output voltage with the battery voltage and preventing the battery from overcharging.
Monitoring the LCD to ensure the display matches the current behaviour of the system

1.4 SIGNIFICANCE OF THE PROJECT
The assemblage of solar battery with charge controller is of great significance as it gives the students a hands-on experience on modern day electrical/electronic equipment. It serves to broaden the students horizon and to unveil the challenges and possible flaws that are associated with charge controllers in the market while encouraging more research into the field.
The charge controller is applied in the following areas:
Charging the batteries used in solar home system, hospitals or industries
Solar lantern in rural area
Cell phone charging

1.5 SCOPE OF STUDY
This project work covers only the assemblage of a solar battery with charge controller for the regulation of current and voltage coming into the battery bank. The design takes into cognizance of the fact that the charge controller is a Maximum Power Point Tracking (MPPT) charge controller which is more efficient..

1.6 METHODOLOGY
To achieve the aim and objectives of this work, the following are the steps involved:
Construct a fly back converter as the charge controller of solar home system.
Simulate this DC to DC converter circuit in LTSPICE simulation platform.
Then implement it in the PCB board. PCB board is designed in express PCB platform.
For easy and better understanding a simplified block diagram of this system is illustrated below;

Fig. 1.0: Simplified block diagram of the model.

1.7 DEFINITION OF TERMS
RELAY: This is an electromagnetic switch. Switching on/off of relays is based on the flow of current through its coil. Relay is used for switching on/off various high voltage circuits. Changeover switch.
TRANSFORMER: This a device used for stepping up and down of voltages. Transformer is one of the most important components of the automatic changeover switch. The job of the transformer is to step down 220v to15v as the output of the automatic changeover switch.
RECTIFIERS: The rectifier circuit consists of a rectifies in series with the AC input to rectifies and the load requiring the DC output i.e. it convert AC to DC.
DIODE: These are two terminal devices which exhibit low resistance to current flow in one direction and hinder resistance to resistance to current in the other direction. Diode is electronic components.
CAPACITORS: These are passive components that provide a means of storing electrical energy in form of an electric field.
REGULATOR: These are device that are used control the rate of current or voltage that from in a process.
LIGHT EMITTING DIODE (LED): This is a small semiconductor devices which emit light when small forward current is applied to them.
RESISTORS: These are defines as devices that alter or resist the flow of current in an electric circuit.
POWER OUTAGE/ POWER FAILURE: is the loss of the electrical power network supply to an end user.
AUTOMATIC CHANGEOVER: is device that automatically transfers power from generator supply to PHCN supply when available and stops the generator without human intervention.

CHAPTER TWO

2.0 LITERATURE REVIEW
2.1 RENEWABLE ENERGY
Renewable energy is energy created from natural sources. This includes sunlight, wind, rain, tides and geothermal heat. With global warming, such as climate change, concerns linked to high oil prices, the drive for more renewable energy is being lobbied by local governments (Ch. Brunner, 2002). Not only would renewable energy help with the global warming concerns, but also may help turn around the recent economic crisis. This would mean less money spent on expensive fossil fuels and more focus on renewable energy sources. So world energy now requires renewable sources to sustain more power accuracy in future. Among the natural sources sunlight is more essential to mankind. Using this source power can be generated within cheap rate (M. Gohul, et al., 2009). Power failure in Bangladesh is a major issue and this condition is degrading with time. People are making themselves dependent on power backup machines such as Instant Power Supply (IPS), generator, Uninterruptible Power Supply (UPS) etc. These machines have a high market value and besides they require expensive maintenance such as fuelling the generator at regular interval, high electricity bill for charging an IPS, checking the distilled water in IPS. Still there are many rural areas in third world countries where the power transmission lines have not been provided yet. As a consequence people leaving over those areas have no other way but to suffer from lack of electricity using the energy of sun, solar panels at home, is the best solution to all these problems. To make this system more efficient and cost-effective it is better to use a dc-dc converter to charge a battery instead of using a simple charge controller (Sabuj D.G., et al., 2014).
There are some conventional charge controllers, which have some problems of charging system. So these charge controllers cannot charge batteries at some extent. To overcome these problems a new type of dc to dc converter, naming fly back converter has been introduced. A block diagram of the conventional charge controller is given below:

Fig. 2.1: Conventional charge controller.
The conventional charge controller of solar home system has the following disadvantages:

1. it provides inadequate current during low sunlight.
2. It cannot support a solar panel of high voltage.
3. In the conventional charge controller excessive power loss occurs in the transmission line between solar panel and charge controller.
4. In the conventional system the panel gets shorted when the battery is completely charged, which affects the panel longevity.
5. In this circuit MPPT (Maximum Power Point Tracking) cannot be introduced (Sabuj D.G., et al., 2014).

To overcome these shortcomings, a new type of dc to dc converter (fly back converter) is introduced. The advantages of using this converter over the conventional charge controller are:

1. It can take variable panel voltage.
2. Its efficiency is better than the conventional one as it reduces wire loss.
3. It is suitable for micro-grid.
4. No panel- short circuit occurs here.
5. It is possible to add MPPT (Maximum Power Point Tracking) with our system (Sabuj D.G., et al., 2014).

2.2 OVERVIEW
A charge controller is needed in photovoltaic system to safely charge sealed lead acid battery. The most basic function of a charge controller is to prevent battery overcharging. If battery is allowed to routinely overcharge, their life expectancy will be dramatically reduced. A charge controller will sense the battery voltage, and reduce or stop the charging current when the voltage gets high enough. This is especially important with sealed lead acid battery where we cannot replace the water that is lost during overcharging. Unlike Wind or Hydro System charge controller, PV charge controller can open the circuit when the battery is full without any harm to the modules. Most PV charge controller simply opens or restricts the circuit between the battery and PV array when the voltage rises to a set point. Then, as the battery absorbs the excess electrons and voltage begins dropping, the controller will turn back on. Some charge controllers have these voltage points factory-preset and non-adjustable, other controllers can be adjustable (German, 2016).
Electricity generations of solar panels are strongly related with solar radiation intensity. However the intensity is not stable. Therefore, charge efficiency is a very important topic in solar systems. Charge controllers are designed to improve charge efficiency and safety. The figure 2.2 below shows the front view of a typical charge controller:

Fig. 2.2: Front View of a PV Charge Controller
[source: intelligent charge controller design]Where:

1. Battery LED indicator
2. LCD display
3. Reset button
4. Temperature sensor
5. 12V DC load terminal with Low Voltage Disconnect
6. 12V battery connection terminal
7. PV panel connection terminal
8. Remote Signal Terminal
9. Side Door (open to access switches for settings)

2.2.1 REVIEW OF THE EXISTING THEORY IN SOLAR CHARGE CONTROLLER POWER SYSTEM
The primary function of a charge controller is to protect the battery from overcharge and over discharge in a stand-alone PV system (REN, 2016). There are a lot of studies about the charge controller in the literature.
Harrington and Dunlop (1992) analyzed the typical strategies for battery charge regulation in stand-alone PV systems and conclude that the battery information is very important in designing PV systems. Ullah focused on the design of a super-fast battery charger based on Nationals proprietary neural network based neural fuzzy technology in 1996. They compared their method with conventional fast chargers and indicate that their method reduce the charging time (Tam Hunt, 2015).
Masheleni and Carelse in 1997 designed an intelligent charge controller, incorporating an SGSThompson microcontroller, ST62E20 and discussed the advantages of such charge controllers. Hsieh in 2001 proposed a fuzzy-controlled active state of- charge controller (FC-ASCC) for improving the charging behaviour of a lithiumion (Liion) battery. In this method, a fuzzy-controlled algorithm is built with the predicted charger performance to program the charging trajectory faster and to remain the charge operation in a proposed safe-charge area (SCA). They increased the charging speed about 23%. Yi presented a novel switch-mode charger controller IC in 2007 for improve the charging efficiency of valve regulated lead-acid (VRLA) battery and save its life.
They achieved fast transient response and the precisions of both constant current and constant voltage charge modes met the specifications well (Bullis, K., 2006).
Chiang (2009) presented the modeling and controller design of the PV charger system implemented with the single-ended primary inductance converter (SEPIC) and gave a detailed modeling of the SEPIC with the PV module input and peak-current-mode control. The system has been proved to be effective in the MPPT and power balance control. The MPPT controller was implemented with the Matlab real-time control in their study.
Tesfahunegn (2011) proposed a new solar/battery charge controller that combines both MPPT and overvoltage controls as single control function. They conducted two case studies in Simulink/Simpower, first to evaluate the performance of the designed controller in terms of transient response and voltage overshoot. Secondly, realistic irradiance data is used to evaluate the performance of the developed charge controller in terms of parameters such as PV energy utilization factor and overvoltage compared to the conventional hysteretic on/off controller. They achieved good transient response with only small voltage overshoot, better in terms PV energy utilization and same level of overvoltage control (Bazilian M. et al., 2013).
Dakkak and Hasan (2012) analyzed a charge controller based on microcontroller in stand-alone PV systems and concluded that such systems reduce the power consumption for charging battery and give flexibility to the designer (Swanson, 2009).
Karami (2012) focused on the load type and suggest new methods to reach the MPP depending on the load state and the development of the PV array mathematical model. They analyzed the effect of temperature and irradiance on the battery charger and showed the difference between the direct-coupled and the indirect-coupled applications of a PV panel (Branker, K. et al., 2011).

2.3 SYSTEM DESCRIPTION
In the review of a charge controller, one must not fail to mention that the charge controller is a part of the solar family set-up and this solar family set-up make up the complete system description. This solar family setup is briefly reviewed below and consists of:

• Solar panel
• Battery
• Charge controller
• Maximum Power Point Tracker
• DC DC converter

2.3.1 Solar Panel
A solar panel is a packaged connected assembly of photovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications. Solar panels use light energy photon from the sun to generate electricity through the photovoltaic effect. The majority of modules use wafer based cells or thin film cells based on non-magnetic conductive transition metals, telluride or silicon. Electrical connections are made in series to achieve a desired output voltage and or in parallel to provide a desired current capability. The conducting wires that take the current off the panels may contain silver, copper or other nonmagnetic conductive transition metals. The cells must be connected electrically to one another and to the rest of the system. Each panel is rated by its DC output power under standard test conditions, and typically ranges from 100 to 320 watts. Depending on construction, photovoltaic panels can produce electricity from a range of light frequencies, but usually cannot cover the entire solar range (specifically, ultraviolet and low or diffused light).
Hence, much of the incident sun light energy is wasted by solar panels, and they can give far higher efficiencies if illuminated with monochromatic light. The figure below shows the interconnection of solar panels.

Plate 2.3: Interconnection of solar panels [source: Fort Benning Solar]

The advantages of solar panels are:

• They are the most readily available solar technology.
• They can last a lifetime.
• They are required little maintenance.
• They operate best on bright days with little or no obstruction to incident sunlight.

2.3.2 Battery
In stand-alone photovoltaic system, the electrical energy produced by the PV array cannot always be used when it is produced because the demand for energy does not always coincide with its production. Electrical storage batteries are commonly used in PV system. The figure below shows a typical 12V 200Ah solar battery:

Plate 2.4: A typical solar battery [source: kingdom power company]

The primary functions of a storage battery in a PV system are:

1. Energy Storage Capacity and Autonomy: to store electrical energy when it is produced by the PV array and to supply energy to electrical loads as needed or on demand.
2. Voltage and Current Stabilization: to supply power to electrical loads at stable voltages and currents, by suppressing or smoothing out transients that may occur in PV system.
3. Supply Surge Currents: to supply surge or high peak operating currents to electrical loads or appliances.

2.3.3 Charge Controller
A charge controller or charge regulator limits the rate at which electric current is added to or drawn from electric batteries. It prevents overcharging and may prevent against overvoltage, which can reduce battery performance or lifespan, and may pose a safety risk. It may also prevent completely draining (“deep discharging”) a battery, or perform controlled discharges, depending on the battery technology, to protect battery life. The figure 2.5 below shows a typical charge controller.

Plate 2.5: A typical charge controller [source: china solar power]
In simple words, Solar Charge controller is a device, which controls the battery charging from solar cell and also controls the battery drain by load. The simple Solar Charge controller checks the battery whether it requires charging and if yes it checks the availability of solar power and starts charging the battery. Whenever controller found that the battery has reached the full charging voltage levels, it then stops the charging from solar cell. On the other hand, when it found no solar power available then it assumes that it is night time and switch on the load. It keeps on the load until the battery reached to its minimum voltage levels to prevent the battery dip-discharge (Encyclobeamia.solarbotics.net). Simultaneously Charge controller also gives the indications like battery dip discharge, load on, charging on etc.
In this design we are using microcontroller based charge controller. Microcontroller is a kind of miniature computer containing a processor core, memory, and programmable input/output peripherals.

The Functions of a microcontroller in charge controller are:

1. Measures Solar Cell Voltage.
2. Measures Battery Voltage.
3. Decides when to start battery charging.
4. Decides when to stop battery charging.
5. Decides when to switch on the load.
6. Decides when to switch off the load.
7. Most importantly in this design, microcontroller also tracks the MPP of the output power.

2.3.4 Maximum Power Point Tracker
The maximum power point tracker (MPPT) is now prevalent in grid-tied PV power system and is becoming more popular in stand-alone systems. MPPT is a power electronic device interconnecting a PV power source and a load, maximizes the power output from a PV module or array with varying operating conditions, and therefore maximizes the system efficiency (www.Encyclobeamia.solarbotics.net.).
MPPT is made up with a switch-mode DC-DC converter and a controller. For grid-tied systems, a switch-mode inverter sometimes fills the role of MPPT. Otherwise, it is combined with a DC-DC converter that performs the MPPT function.
2.3.5 DC-DC Converter
DC-DC converters are power electronic circuits that convert a dc voltage to a different dc voltage level, often providing a regulated output. The key ingredient of MPPT hardware is a switch-mode DC-DC converter. It is widely used in DC power supplies and DC motor drives for the purpose of converting unregulated DC input into a controlled DC output at a desired voltage level.
MPPT uses the same converter for a different purpose, regulating the input voltage at the PV MPP and providing load matching for the maximum power transfer. There are a number of different topologies for DC-DC converters. In this design we are using DC-DC converter as it is obtained by using the duality principle on the circuit of a boost converter (www.Encyclobeamia.solarbotics.net.).

2.4 THE CHARGE CONTROLLER
2.4.1 Working Principle of a Charge Controller
The basic components of a solar charge controller (especially that used for this design) are:

• Microcontroller
• Boost converter
• MOSFET
• Voltage sensor
• Liquid Crystal Display (LCD)
• Light Emitting Diode (LED)

There are other components like the power inductor, capacitors, resistors, diodes etcetera. The working circuit diagram is shown in the figure below:

Figure 2.6: Working circuit diagram of a charge controller (source: solar energy Centre)

From the circuit diagram above, it can be seen that the voltage from the solar panel first comes to the boost converter circuit which does the job of stepping up the input DC voltage to get a higher DC output voltage if the input voltage is lower than the specified rating (12V in this case). The boost converter is connected to the voltage sensor which is further interconnected to the microcontroller. The function of the microcontroller has already been established earlier in this chapter.
The LED indicates when the charge controller is charging the battery and when it is fully charged while the LCD displays the battery voltage and panel input voltage. Generally, there are two types of charge controllers namely:

• The Pulse Width Modulation (PWM)
• The Maximum Power Point Tracking (MPPT)

2.4.2 Pulse Width Modulation Charge Controller
Pulse Width Modulation (PWM) charge controllers are simple and more affordable. It uses a series of pulses to charge the battery. It regulates the voltage by varying the width of the pulse. If it wants to increase the voltage, it increases the pulse width and when it wants to lower the voltage, it reduces the pulse width (Palz, W., 2013).
The technology behind Pulse Width Modulation (PWM) charge controllers is one of the most popular charge controller technologies on the market today. A time-tested technology that has been used for many years in solar photovoltaic (PV) systems with batteries, it is also needed for wind, hydro, fuel, or utility grid. PWM charge controllers are inexpensive (when compared to MPPT charge controllers), available in different amperages, and highly durable. PWMs help to regulate often inconsistent voltage put out by power sources (for example solar panels) in order to protect the system batteries from overcharging. When the solar array has the PWM mode activated, the charge controller uniquely handles the job of battery charging by constantly checking the current battery and self-adjusting accordingly to send only the right amount of charge to the battery.
This type of charge controller works by reducing the current from the power source according to the batterys condition and recharging requirements. The PWM charge controller does this by checking the state of the battery to determine both how long (wide) the pulses should be as well as how fast they should come (Jacobson, M.Z. 2009). With this information, the PWM charge controller then self-adjusts and sends the appropriate pulse to charge the battery it varies the length and speed of the pulses sent to the battery as needed. This is a rapid on and off switch. When the battery is nearly discharged, the pulses may be long and continuous, and as it becomes charged, the pulses become shorter or trickled off. This trickle or finish type charging mode is important for systems that can go days or weeks with excess energy during periods when very little of the solar energy is consumed (Jacobson, M.Z. 2009).
This type of charge controller is ideal for solar arrays where excess energy is a regular occurrence, and provide several key benefits: higher charging efficiency, rapid recharging, and healthier batteries that operate at full capacity.
2.5 BENEFITS OF USING A PWM CHARGE CONTROLLER
Traditional systems for charging solar system batteries relied on on-off regulators to limit battery out gassing during periods of excess energy production, but this often resulted in early battery failures and increased load disconnects. With a PWM algorithm, the charge controller can slowly reduce the charging current to prevent problems like gassing and overheating of the battery (Jacobson, M.Z. 2009). The benefits are thus:

1. Battery Aging Adjustments: By automatically adjusting to the batterys needs, a PWM charge controller will overcome traditional problems with charge acceptance seen in older batteries.
2. Battery Gassing and Heat Reductions: By recharging more quickly than other charge controllers, a PWM avoids problems with gassing and heating which damage the battery.
3. Charge Acceptance Increase: Charge acceptance is a necessity with solar system batteries, though this has typically been a problem in solar arrays. A PWM algorithm, however, increases the charge acceptance of the battery so that more of the energy generated by the array gets captured.
4. Drifting Battery Cell Equalization: Many PWM charge controllers hold battery cells in better balance through equalization, which evens out the acceptance of charge to avoid capacity deterioration.
5. High Battery Capacity Maintenance: The state-of-charge should remain high in order to maintain a healthy system and preserve the life of the battery. PWM algorithms provide better battery capacity maintenance due to the increased number of charge/discharge cycles.
6. Lost Battery Recovery: Sulfation of lead-acid batteries in solar systems is a significant problem due to extended undercharging, which results in grid corrosion and sulfate crystal formation on the batterys positive plates. PWM charge controllers have been shown to recover lost capacity over time by deterring sulfate deposit formation, and pushing through corrosion at the interface.
7. Self-Regulation with Drops in Voltage or Temperature: Older charge controllers can be negatively impacted by temperature effects or voltage drops, creating problems with the final charge of the battery. But a PWM charge controller will taper the charge to minimize these impacts.
8. Taken together, these PWM advantages can be very attractive to PV owners looking for a simpler way to manage their solar set-up.

2.5.1 Maximum Power Point Tracker Charge Controller
The MPPT charge controller tries to keep the voltage and the power stable. The MPPT charge controller will harvest more power from the solar array it will adjust its input voltage to harvest the maximum power from the solar array and the transform this power to supply the varying voltage requirement of the battery plus load (Jacobson, M.Z. 2009).
An MPPT charge controller is an electronic DC to DC converter that optimizes the match between the solar array (PV panels), and the battery bank or utility grid. To put it simply they convert a higher voltage DC output from solar panels down to the lower voltage needed to charge batteries or vice-versa. Maximum Power Point Tracking is electronic tracking usually digital. The charge controller looks at the output of the panels, and compares it to the battery voltage. It then figures out what is the best power that the panel can put out to charge the battery. It takes this and converts it to the best voltage to get maximum amps into the battery. Most modern MPPTs are around 93-97% efficient in the conversion (Jacobson, M.Z. 2009).
The power point tracker is a high frequency DC to DC converter. They take the DC input from the solar panels, change it to high frequency AC, and convert it back down to a different DC voltage and current followed by the output regulator to exactly match the panels to the batteries. MPPTs operate at very high audio frequencies, usually in the 20-100kHZ range. The advantage of high frequency circuits is that they can be designed with very high efficiency transformers and small components. The design of high frequency circuits can be very tricky because of problems with portions of the circuit broadcasting just like a radio transmitter, causing radio and TV interference. Noise isolation and suppression becomes very important.
2.5.2 Effectiveness of the MPPT
MPPTs are most effective under these conditions:

• Winter, and/or cloudy or hazy days – when the extra power is needed the most.
• Cold weather – solar panels work better at cold temperatures, but without a MPPT you are losing most of that. Cold weather is most likely in winter – the time when sun hours are low and you need the power to recharge batteries the most.
• Low battery charge – the lower the state of charge in your battery, the more current an MPPT puts into them – another time when the extra power is needed the most. You can have both of these conditions at the same time.
• Long wire runs – If you are charging a 12 volt battery, and your panels are 100 feet away, the voltage drop and power loss can be considerable unless you use very large wire. That can be very expensive. But if you have four 12V panels wired in series for 48 volts, the power loss is much less, and the controller will convert that high voltage to 12 volts at the battery. That also means that if you have a high voltage panel setup feeding the controller, you can use much smaller wire.

2.5.3 Smart Power Trackers
Charge controllers for solar panels need to be a lot more smart as light and temperature conditions vary continuously all day long, and battery voltage changes All recent models of digital MPPT controllers available are microprocessor controlled. They know when to adjust the output that is being sent to the battery, and they actually shut down for a few microseconds and look at the solar panel and battery and make any needed adjustments.
Although not really new (the Australian company AERL had some as early as 1985), it has been only recently that electronic microprocessors have become cheap enough to be cost effective in smaller systems (less than 1kW of panel). MPPT charge controllers are now manufactured by several companies, such as Outback Power, Xantrex XW-SCC, Blue Sky Energy, Apollo Solar, Midnite Solar, Morningstar and a few others (Jacobson, M.Z. 2009).
2.5.4 Preference of MPPT Charge Controller over PWM for the design
MPPT is at least 30% more efficient than PWM. PWM have been around for ages and rely on old technology. They work to match the voltage of the panel to battery voltage and pulls down the panel output voltage in doing so.
Another downside to the PWM is that it also creates interference in radios and TVs due to the sharp pulses that it generates.
The MPPT charge controllers offer a potential increase in charging percentages, offers up to 80 amps sizes, MPPT charge controller warranties are typically longer than PWM and offer great flexibility for system growth.

CHAPTER THREE

3.0 RESEARCH METHODOLOGY
3.1 Brief Outline of the Chapter
This chapter includes the research methodology, different forms of component that make up the solar photovoltaic system such as the battery bank, the solar charger controller and the load (appliance) were. Also discussed.

3.2 RESEARCH DESIGN
The first step in understanding a solar photovoltaic system is to find out total power and energy consumption of all loads that are needed to be supplied by the solar photovoltaic system as follow:
Calculating the total watt hour per day needed from the photovoltaic modules.
This is done by multiplying the total appliances with hours per day the energy loss factor in the system to get total watt- hours per day which must be delivered to the appliances.
These following stages were adopted:

• Power supply
• Power Transformer
• Voltage Regulator
• The Inverter Stage
• Inverter Sizing

POWER SUPPLY
All electronic equipment needed to be energized by means of electric power supply. An inverter uses a 12V accumulated battery.

It supplies 12V to the input of the voltage regulator that regulates it to a stable and constant supply to power the control circuit.

POWER TRANSFORMER
A transformer is a device of two coils called primary and secondary coil. The Alternating Current voltage applied to the primary coil appears across the secondary coil by electromagnetic induction.

Power transformers convert incoming Alternating current (AC) power from the incoming voltage to a different voltage by a process called electromagnetic induction, the generation of an electric current by passing metal wire through a magnetic field used in electronic circuit; they generally provide power to an electronic device at a steady voltage, solving the problem of voltage fluctuation (Electrical 4u (2014).

Fig. 3. 1 Transformer

If the input (primary) has more turn than the output, the secondary voltage is smaller than the primary voltage.
Ns =number of turn in secondary
Np=number of turn in primary
Ep=primary voltage / input voltage
Es=secondary voltage / output voltage
Is=secondary current
Ip=primary current

  Ns/Np=Es/Ep=Ip/Is

VOLTAGE REGULATOR
A voltage regulator is piece of equipments designed for the maintenance of a constant level of voltage. Several types of voltage regulator exist and has their own advantages and disadvantages. Most voltage regulator work by using an internal fixed voltage as a reference to be compared to the voltage being put out.
Voltage regulator is an integrated circuit component that gives a constant output voltage supply. Voltage regulator can be divided into fixed and adjustable regulator. The three terminals of the fixed voltage regulator are the input, common and the output terminals while those of the adjustable voltage regulator are the input, output and adjustment terminals.

There are four types of voltage regulator
SERIES PASS VOLTAGE REGULATOR
Series pass regulators are considered the least effective of voltage regulator. Its power is continuously dissipated. Thus making it more reliable than other type.
SHUT VOLTAGE REGULATOR
They are more efficient than the series types because, their power is usually none dissipated until the battery approaches full capacity.
STEP DOWN SERIES SWITCH REGULATOR
The step down series switch regulator, like the series type regulator, increases efficiency at the voltage output increases. The increases complexity of the circuitry, however, makes this type less reliable than either the series pass or shut type.
STEP-UP SHUT SWITCHING REGULATING
It has the highest efficiency as a result of its complex circuitry. That complexity makes the cost of this type of regulator so high that its impractical to use for certain purposes.

COMPONENT OF VOLTAGE REGULATOR

• Capacitor
• Resistor
• Diode
• Transistor

THE INVERTER STAGES
The inverter unit is made of, sourcing, regulating, oscillating, driving, transformation, output, change over, battery charger, and MOSFET driver.
SOURCING STAGE: This stage consists mainly of direct current (D.C) battery and in this case is from solar panel . The battery provides 12V direct current (D. C) supply to the inverter system when the alternating current (A. C) from the main supply fails.
REGULATING STAGE : The regulating stage consists of an Integrated Circuit voltage regulator. This is a three pm 9V. integrated Circuit voltage regulator it is a simple precision regulator that regulates the supplied voltage of 12V from battery. The regulated voltage is then used by the oscillator to come on.
OSCILLATING STAGE: The oscillating stage is the heart of inverter design. An oscillator is essentially an electronic circuit designed to produce an alternating current signal of the known frequency and wave form. The inverter system needs to generate signal at 50Hz as which is sent driver for amplification through the pin 11 and 14 Integrated Circuit.
DRIVING STAGE: The driving stage is required to drive the current derived from the output of the oscillator to the amplifier. The stage consists of metallic oxide semiconductor field effect transistor (MOSFET) which has high impedance.

The transistor user are both PNP and NPN transistor which are connected in a push-pull arrangement. The MOSFET driver stage does not match the oscillator to amplifier but also ensure that the stage of the MOSFET when in parallel are properly isolated from each other even when they are driven by the gate of the MOSFETs which result in the MOSFETS channel being alternatively switched on and off. That its when one second MOSFET channel which is a crucial process in the outlet section is repeatedly 50 tons per seconds that is at frequency of 50Hz.
TRANSFORMATION STAGE: Here, a step-up transformer is used. It is a type of transformer used for increasing voltage supply to the output. The step-up transformer consists of two coils called primary and secondary coils, wounded round a soft iron that is made of sheet of soft iron.
The secondary coil of this type of transformer is however greater than the number of turns in the primary coil.

The primary winding of the step-up transformer is 24V-0V-240V and the secondary winding is transferred to the socket outlet of the output of the inverter system.
OUTPUT STAGE: In this stage, the Alternating Current voltage produced by the inverter reaches socket output the action of the pulse width modulation (PWM) of the Integrated Circuit, Also, the expected load is connected through this socket outlet so as to power it.

CHANGE OVER STAGE: The change over stage takes the center stage when the alternating current main supply is off, then the yellow led indicator comes on indicating that the inverter has started to operate on the battery mode and when the alternating current supply returns, the green led indicator is on then inverter.

SOLAR CHARGED CONTROLLER SIZING
The solar charge controller is typically against amperage and voltage of photovoltaic away and batteries then identify which type of solar charge controller is right for the application. The solar charge controller must have enough capability to handle the current from photovoltaic arrays.

For the series charge controller type, the sizing of controlled depends on the total photovoltaic input current which is delivered to the controller and depends also or photovoltaic panel configuration (series or parallel configuration). According to the standard practice, the sizing of solar charge controller is to take the start circuit (ISC) of the photovoltaic array and multiply it by 1.3 solar charge controller =(total short circuit current rating of VP x 1.3)

3.3 BLOCK BY BLOCK (UNIT BY UNIT BLOCK DIAGRAM OF THE PROJECT)

Fig. 3.2 Block Diagram of a solar battery charger

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PROJECT PREPARED BY
ADEGOKE ABDULBASIT ARAMIDE 2018702030023
ADEGOROYE ISKILU BOLAJI 2018702030024
ADEKOLA TOHEEB BABATUNDE 2018702030026
ADEKOYA OLANREWAJU OLUWASEUN 2018702030027
ADEMUWAGUN CHRISTOPHER BAMISE 2018702030028

A PROJECT REPORT SUBMITTED TO THE DEPARTMENT OF ELECTRICAL ENGINEERING IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF NATIONAL DIPLOMA IN ELECTRICAL ENGINEERING OF
THE POLYTECHNIC, IBADAN

JULY 2021.

CERTIFICATION

This is to certify that this project work “CONSTRUCTION OF KRYPAD ACCESS CONTROL LOCK WITH CARD” was carried out by the following students of the department of ELECTRICAL ENGINEERING, The Polytechnic, Ibadan.
ADEGOKE ABDULBASIT ARAMIDE 2018702030023
ADEGOROYE ISKILU BOLAJI 2018702030024
ADEKOLA TOHEEB BABATUNDE 2018702030026
ADEKOYA OLANREWAJU OLUWASEUN 2018702030027
ADEMUWAGUN CHRISTOPHER BAMISE 2018702030028

DEDICATION

This project is dedicated to God Almighty, the author of wisdom, understanding and knowledge

ACKNOWLEDGMENT

We give glory, honor and adoration to almighty God, who is the Alpha and Omega who had made it easier for us through this project.
We also appreciate our supervisor MR. M. O. AYENI for his effort, encouragement, advice and support, when we undertake this project our sincere gratitude also goes to our parents, siblings and those who contribute immensely to the completion of the project.

ABSTRACT

The main purpose of this project is to design and implement a system based on a password using Radio-Frequency Identification RFID. This system is basically a password and an RFID based access-control system which permits only an authorized person to unlock. For doing this, the system will activate and authenticate the user. Application of a security system via a passive ID number form RFID tag was used. Then enter the password from a keypad, if the ID number of the tag and password are correct, then it will unlock. The aim of constructing this system is to put in place a formidable locker security system with low cost and free of errors. Keywords – RFID Reader, Atmega328p, Keypad, LCD, Buzzer. The security system plays a significant role to keep out unknown users to access protected physical and logical places with no permission. Furthermore, unwanted people can hack the lock and have access to the protected place. It can further be use for smart cart can be interfaced with wireless technologies to make it completely portable in the nearest future.

TABLE OF CONTENT

Pages
Title page i
Certification ii
Dedication iii
Acknowledgement iv
Abstract v
Table of content vi-x
CHAPTER ONE
1.0 Introduction 1
1.1 Background of Study 1-2
1.2 Statement of Problem 2
1.3 Research Objectives 3
1.4 Expected Contribution to Knowledge 3
1.5 Limitations/Scope of Project 3-4
1.6 Methodology 4
Definition of Terms 4-6
CHAPTER TWO
2.0 Literature Review 7
2.1 Brief Outline of the Chapter 7
2.2 Historical Background of the Project 7-10
2.3 Theories/Concept Related to Project 10-11
2.3.1 Readers 11
2.3.2 Signaling 11-12
CHAPTER THREE
3.0 Research Methodology 13
3.1 Brief Outline of the Chapter 13
3.2 Research Design 13
3.3 Block by Block, Unit by Unit Design of the Project 13 -14
3.3.1. Radio-frequency Identification 14-15
3.3.2 Keypad 15-16
3.3.4. A Microcontroller 16-18
3.3.4. LCD 18-19
3.3.5 Solenoid Lock 19-21
CHAPTER FOUR
4.0 Principle of Operation 22
4.1 A brief Outline of the Chapter 22
4.2 Principle of Operation of the Project 22
4.3 Explanation of the various unit (block) in the Project 22
4.3.1 The power supply Unit 22-24
4.3.2 Micro Controller Unit 24
4.3.3. RFID reader Unit 25
4.3.4 Keypad Unit 25

CHAPTER FIVE
5.0 Construction of the Design Project 26
5.1 Brief Outline of the Chapter 26
5.2 Choice of Materials 26-30
5.3 Construction of the Project 31
5.4 Bill of Engineering Measurement and Evaluation (BEME) 31
5.5 Test and Result 32-33
CHAPTER SIX
6.0 Conclusion, Summary and Recommendations 34
6.1 Summary of the Project Chapter by Chapter 34
6.2 Problems Encountered 34-35
6.3 Recommendation 35-36
6.4 Conclusion 36

LIST OF FIGURES
Fig 2.1 RFID hard tag 11
FIG 3.1 Block diagram of the construction of keypad access control lock with card and buzzer alarm system 13
Fig 3.2 RFID Module 14
Fig 3.3 RFID Tag 15
Fig 3.4 KEYPAD Module 16
Fig 3.5 ATMega328P Pin out 17
Fig 3.6 LCD Module 18
Fig 3.7 Solenoid Lock 20
Fig 4.1 Schematic Diagram of Keypad Access Control Lock with Card 21
Fig 4.2 Circuit diagram of Power Supply Unit 22
Fig 4.2 Pin Configuration 24
Fig 4.3 RFID reader unit 25
Fig 4.4 Keypad 25
Fig 5.1 Construction of the Project 31
Fig 5.2 Testing of the Project 33

LIST OF TABLE
Table 5.1: Bill of Engineering Measurement and Evaluation (BEME) 32

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A Project write-up on Solar Powered Mobile Phone Charger

A PROJECT WRITE-UP ON INVERTER

ABSTRACT
This project, solar powered mobile phone charger is designed for use in mobile phones and other gadgets which uses a 5v input for charging. The circuit makes use of a microprocessor (LM256T-ADJ) to create a buck converter which steps down the voltage from the solar panel to suit the level of voltage needed by the mobile phone. The use of this charger guarantee’s the safety of mobile phones being charged as it is being charged in range and at one’s comfort

CHAPTER ONE (1)

INTRODUCTION

BACKGROUND OF THE STUDY
Portable Solar Mobile Phone Charger is a power electronic device that converts the sun’s radiation into electrical energy for the purpose of charging the batteries of mobile phones. It does this by converting, controlling and conditioning the flow of electrical energy from source (solar panel) to load (mobile phone) according to the requirements of the load.
In a densely populated, poverty-stricken country with a population of over 160 million people in the case of Nigeria, it is unarguable that the epileptic state of power supply is an issue of great concern to Nigerians. Citizens find it very difficult to charge their phones when they eventually have a flat battery. We are now left with the option of putting on a generating set (Generator) which causes air pollution and depletion of the atmospheric ozone layer (greenhouse effect), generators are also very expensive to operate due to the hike in price of petrol in the country. The option of charging through public charging centers is inconvenient as most times these centers are crowded and employ the use of a generator as well. Theft of mobile phones is prevalent with charging centers and fire outbreaks in many cases due to overload of supplying cables and very unprofessional connections done in order to realize money as quickly as possible.

1.2 STATEMENT OF THE PROBLEM
Most country are faced with many challenges ranging from air pollution due to smoke from some source of power supply. Lack of effective and reliable power supply system.
The epileptic and incessant power supply in Nigeria in this case Owerri imo state in particular has necessitated once need for this project, cause most student and people always on stand-alone generators to charge up their phone and appliances which can be charge using the USB ported solar charger.
So, there is a need to design and construct the solar panel charger which will complement the electricity supply from the public grid because the reduction injunctive and capacitive load. It is less noisy and does not have any consequence(s) on human health
1.3 AIMS AND OBJECTIVES
1.3.1 Aim:
The aim of this project is to design a cost effective solar powered mobile phone charger, which has a USB port and can also be used to charger other appliance with same input or charging mode
1.3.2 Objectives:
The following are specific objective
i. To design a portable solar charger.
ii. To construct the designed solar mobile phone charger.
iii. To evaluate the performance of the designed charge

1.4 SIGNIFICANCE OF THE STUDY
The project completion will be of great help to country if adopted, in order to maintain a stable power source for mobile phones in country. The use of solar power has advantages firstly the energy from the sun is free and readily accessible in most part of the world. More over the sun will keep shining until end. Also, silicon from which most photovoltaic cell are made is in abundant and nontoxic element. The whole energy conversion process is environmentally friendly.
It produces no-noise, harmful emission or polluting gases. The burning of natural resource of energy can create Smoke, cause acid rain and pollute water and air

CHAPTER TWO

LITERATURE REVIEW

2.1 RELATED WORK
A lot of research work has been carried out on the design of a cost-effective solar power charger. Engr Chinedu P.A Okwaraokwa, Engr Azubogu and Engr M.I Ariguzo researched on a cost effective solar charger controller for lithium ion battery using 555 time IC in 2016. in this work an 8 watt photovoltaic (PV) Panel successfully used to charge a lithium ion battery using a custom designed and constructed pulse width modulated(PWM) solar charge controller . The charger controller includes automatic cut off to prevent battery overcharge (international journal of electrical and telecommunication system research.
Anurag project a channel on you tube did similar work on the project on 2021, he used 1c78056x1, capacitor 1000ufx2, diode 1n 4007×1, resistor 1kx1 ledx1, USB female port connector x1 and a solar panel 6x2w to construct the project as shown in the diagram.

Figure 2.1
Design and construction of a portable solar mobile charger by salim mudi in the department of telecommunication engineering, federal university of technology, mina Nigeria (2018). The charger was made by converting, controlling and condition the flow of electrical energy from source to load according to the requirement of the load.

2.2 PROJECT ANALYSIS
2.2.1. Solar panel
Solar panels are devices that convert light into electricity. They are called “solar” panels because most of the time, the most powerful source of light available is the Sun, called Sol by astronomers. Some scientists call them photovoltaic’s which means, basically, “light-electricity”.
A solar panel is a collection of solar cells. Lots of small solar cells spread over a large area can work together to provide enough power to be useful. The more light that hits the cell, the more electricity it produces. Solar panels generate free power from the sun by converting sunlight to electricity with no moving parts, zero emissions, and no maintenance. The solar panel, the first component of an electric solar energy system, is a collection of individual silicon cells that generate electricity from sunlight. The photons (light particles) produce an electrical current as they strike the surface of the thin silicon wafers. A single solar cell produces only about 1/2 (.5) of a volt. Multiple solar panels can be wired in parallel to increase current capacity (more power) and wired in series to increase voltage for 24, 48, or even higher voltage systems. The advantage of using a higher voltage output at the solar panels is that smaller wire sizes can be used to transfer the electric power from the solar panel array to the charge controller & batteries Embark electronics.
The solar panel is made up of the following:
The semiconductor material which absorbs light and converts it into electron-hole pairs.
The junction formed within the semiconductor, which separates the photo-generated carriers (Electrons and holes).
The contacts on the front and back of the cell that allow the current to flow to the external circuit.
The glass sheet that protects the semiconductors and also prevent reflection of the sun rays.
The frame that holds the whole component together as one component.
The terminals where the generated direct current is tapped from.

Figure 2.2.1 Shows Cell- Module- Panel- Array

Multiple modules can be wired together to form an array. In general, the larger the area of a module or array, the more electricity that will be produced. Photovoltaic modules and arrays produce direct-current (dc) electricity.

2.2.2 Types of Solar Panels
Basically, there are three basic types of solar panels and they include;
Monocrystalline Solar Panels
Polycrystalline Solar Panels
Amorphous solar panels

Monocrystalline Solar Panels: The most efficient and expensive solar panels are made with Monocrystalline cells. These solar cells use very pure silicon and involve a complicated crystal growth process. Long silicon rods are produced which are cut into slices of .2 to .4 mm thick discs or wafers which are then processed into individual cells that are wired together in the solar panel.

Polycrystalline Solar Panels: Often called Multi-crystalline, solar panels made with Polycrystalline cells are a little less expensive & slightly less efficient than Monocrystalline cells because the cells are not grown in single crystals but in a large block of many crystals. This is what gives them that striking shattered glass appearance. Like Monocrystalline cells, they are also then sliced into wafers to produce the individual cells that make up the solar panel.

Amorphous solar panels: These are not really crystals, but a thin layer of silicon deposited on a base material such as metal or glass to create the solar panel. These Amorphous solar panels are much cheaper, but their energy efficiency is also much less so more square footage is required to produce the same amount of power as the Monocrystalline or Polycrystalline type of solar panel.

2.2.3 Specifications Of Solar Panels
Solar panels have many specifications. The most important values are:
Peak Power
Open Voltage
Short Circuit Current

Peak Power
The peak power is the maximum power that a solar panel can give when it is being operated in full sunlight. The higher the peak power, the higher the energy output of the panel will be.
Open Voltage
The open voltage is the voltage which is measured when the panel is not connected to anything but a voltmeter and pointed to the sun. The open voltage can be used to determine whether is panel is positioned in the right way. The higher the open voltage, the higher the energy output of the panel will be.

Short Circuit Current
The short circuit is the current which is measured when the panel is not connected to anything but a current meter to measure the short circuit current. The higher the short circuit current, the higher the energy output of the panel will be.
2.2.4 Dc to Dc converter
A DC-to-DC converter is an electronic circuit or electromechanical device that converts a source of direct current (DC) from one voltage level to another. It is a type of electric power converter. Power levels range from very low (small batteries) to very high (high-voltage power transmission). DC-to-DC converters are used in portable electronic devices such as cellular phones and laptop computers, which are supplied with power from batteries primarily. Such electronic devices often contain several sub-circuits, each with its own voltage level requirement different from that supplied by the battery or an external supply (sometimes higher or lower than the supply voltage). Additionally, the battery voltage declines as its stored energy is drained. Switched DC to DC converters offer a method to increase voltage from a partially lowered battery voltage thereby saving space instead of using multiple batteries to accomplish the same thing.
Most DC-to-DC converter circuits also regulate the output voltage. Some exceptions include high-efficiency LED power sources, which are a kind of DC to DC converter that regulates the current through the LEDs, and simple charge pumps which double or triple the output voltage.

2.2.5 TYPES OF DC TO DC CONVERTERS
Buck converter
Boost converter

A buck converter (step-down converter) is a DC-to-DC power converter which steps down voltage (while drawing less average current) from its input (supply) to its output (load). It is a class of switched-mode power supply (SMPS) typically containing at least two semiconductors (a diode and a transistor, although modern buck converters frequently replace the diode with a second transistor used for synchronous rectification) and at least one energy storage element, a capacitor, inductor, or the two in combination. To reduce voltage ripple, filters made of capacitors (sometimes in combination with inductors) are normally added to such a converter’s output (load-side filter) and input (supply-side filter). It is called a buck converter because the voltage across the inductor “bucks” or opposes the supply voltage. Switching converters (such as buck converters) provide much greater power efficiency as DC-to-DC converters than linear regulators, which are simpler circuits that lower voltages by dissipating power as heat, but do not step up output current. The efficiency of buck converters can be very high, often over 90%, making them useful for tasks such as converting a computer’s main supply voltage, which is usually 12 V, down to lower voltages needed by USB, DRAM and the CPU, which are usually 5, 3.3 or 1.8 V.

CHAPTER THREE

MATERIALS AND METHOD

3.1 MATERIALS
The following materials were used for the construction, for this project to be completed there is a need to know the component to be used for the design these includes:
Solar panel
Universal serial bus connector
Vero board
16v 1500uf capacitor x6
Buck converter materials:
LM256T-ADJ x1
IN5822 diode x1
Capacitor 100uf x1
Electrolytic capacitor 2200uf x1
Inductor 150uh x1
Potentiometer 47k x1
Through hole resistor 1.2k ohms x1
3.2METHOD
Circuit diagram:

Figure 2.1.2 : showing the circuit diagram of project
3.3 SYSTEM OPERATION
The solar panel absorbs energy produced by the sun and converts it into electrical energy. It does this by absorbing sun rays into the modulus of solar panel hence produce free electrical charge carriers in the conduction and valence bonds. The electricity produced by the solar panel is DC and it is transferred to the capacitor, due to variation in intensity of sunlight to avoid lower or higher voltage which would damage our circuit or device the capacitors are added to store up the charge acting as a battery to provide a steady voltage at input. The input charge is transferred to the buck converter, the buck converter makes use of LM2576T-ADJ microprocessor and it has feedback and output will stay the same using different loads, with it we have feedback pin connected to output voltage divider, the LM256T-ADJ will change the width of the pulse depending on the output in other to keep the output constant. In this project we used a Schottky barrier rectifier diode because it has a load forward voltage; this diode will allow the current to flow when the microprocessor switch is open
3.4 DESIGN CALCULATION
Capacitors:
A capacitor is an electrical device that can store charge or energy. Capacitors can be connected in two ways namely:
Serial capacitor connection.
Parallel capacitor connection.
When capacitors are connected in series the amount of charge output is the addition of the reciprocal of each capacitors charge and the voltage across them is not the same, there is voltage drop across each capacitor
CT = 1/c1 + 1/c2 + 1/c3
Total v = v1 + v2 + v3
In a parallel connection the amount of output charge is the addition of individual charge of each capacitor. The voltage in this type of connection is the same across each capacitor.
CT= C1 + C2 + C3
Total v = v1 = v2 = v3
Therefore, total charge in capacitor = 1500uf x 6 = 9000uf
Voltage =16v
LM2576T-ADJ
The lm2567-adj regulators are monolithic integrated circuit that provides all the active functions of a step-down (buck) switching regulator capable of driving 3A load with excellent line and load regulation.
The LM2576T-ADJ description
Maximum supply voltage = 45V
On/off pin input voltage -0.3v =< V = < +V in
Output voltage to ground
(Steady state). -1V
Power dissipation internally limited
Maximum junction temperature. 150°C
vout = vref(1+R2/R1)
R2 = R1(vout /vref -1)
Where Vref = 1.23v
R1 is between 1k to 5k ohms

When Vout = 5v
Vin = 18v
R1 = 1.2kohms
R2 which is the potentiometer is set to
R2 = 1.2×103 (5/1.23 – 1)
= 3.68k ohms
I load (max) = 3.0A
So the potentiometer will be set to 3.6k for there to be a 5v output for charging the gadget
Inductor
An inductor is a passive electronic component that stores energy in the form of a magnetic field. In its simplest form, an inductor consists of a wire loop or coil. The inductance is directly proportional to the number of turns in the coil. we used the induction selection guide in figure below to select the inductance of the inductor

From the figure above the inductance of inductor needed is L100
Output capacitor
A capacitor of capacitance ranging from 680uf to 2200uf is used at the output , the capacitor should be a standard aluminum electrolytic capacitor. The voltage rating should be 20V .
Input capacitor
A 100uf 25v aluminum electrolytic capacitor is located near the input and ground pin , it provides sufficient bypassing
Catch diode
The buck regulator requires a diode to provide a return path for the inductor current when switch is off. Thus, this diode should be located close to the lm2576t-adj using short leads. Because of their fast switching speed and low forward voltage drop, schottky diodes provide the best efficiency for the project. An in5822 diode was selected.

The voltage of the solar panel increases when exposed to sunlight with respect of time of explosion. Similar, applies to the current and electrical power produced.

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Project write-up for inverter

CIRCUIT THEOREM EEC 222

A resistance of 40Ω, inductance of 0.4Hz and capacitance of 200µF are connected in series and are fed by 200v, 60Hz supply. Find;

1. Inductance Reactance, X_L
2. Capacitance Reactance, X_C
3. Magnitude of impedance, Z of the RLC Circuit
4. Magnitude of admittance, Y of the RLC circuit

SOLUTION

R = 40 Ω, L = O.4H, Capacitance = 200 × 10^-6F, Frequency = 60Hz, Voltage = 200v.

1.  Inductance Reactance, X_L

X_L  = WL = 2ΠF × L   ;      2 × 3.142 × 60 × 0.4

                                      =150.816 Ω

1. Capacitance Reactance, X_C

X_{C =} 1/W_c = 1/2ΠF × C _{= 13.33}Ω

1. Magnitude of impedance, Z of the RLC Circuit

Z =

Z =

Z =  = 143.187Ω

1. Magnitude of admittance, Y of the RLC circuit

Y =   _{=   =}  ^-3 Ω

The velocity of such on a transmission line is given as V = √(1/LC)
Where L = Line inductance per unit length (H/m) i.e Henry per meter
C = Line capacitance per unit length (f/m) i.e farad per meter
V = The velocity of propagation of surge (m/s) meter per seconds
Surge velocity is independent of size and spacing of conductor

Velocity of propagation of surge in underground cable
Where a is the radius of the core
b is the radius of the sheath
C = 2πEo÷inB/A and L = μo/2π • inB/A

NOTE: E = Absolute permittivity of a medium
μ = Absolute permeability of a medium
E = EoEr and μ =μoμr
Eo = Absolute permittivity of free space and Er = relative absolute permittivity
μo = Absolute permeability of free space and μr = relative absolute permeability
For magnetic material V = √(1/LC)
V = √[1/(μo/2π • inB/A × 2πEo÷inB/A)
V = √(1/μoEo)
Eo = 4π × 10–⁷
μo = 1/36π × 10–⁹
V = √(1 ÷ (1/36π × 10–⁹ × 4π × 10–⁷)
V = √(1 ÷ (1/9 × 10–¹⁶ )

The 10–¹⁶ when the power leaves the numerator to the numerator it changes sign from 10–¹⁶ to 10¹⁶
V = √(1 ÷ 0.11 × 10¹⁶)
V = √9.009×10¹⁶
V = 3 × 10⁸m/s

1. Buffer system malfunction message means what?
   A) The label is cut off
   B) The Buffer system is too tension
   C) The label is not properly fixed on the web guilder
   D) None of the above
   The point at which the label is cut off from the buffer there will be buffer system malfunction on the HMI(human machine interface)
   
2. When monitoring three alarm comes on, it means
   A) Missing label at the vacuum cylinder
   B) Untransferred label at the vacuum cylinder
   C) Label not properly positioned on the bottle
   D) Option A and C
   On the labeller machine, one error that is usually displayed on the HMI when three alarm comes on is label carryover also called Untransferred label at the vacuum cylinder
   
3. When monitoring two alarm comes on, it means
   A) No label on the vacuum cylinder
   B) Label on the vacuum cylinder
   C) Missing label between cutter drum and glue roller
   D) None of the above
   When monitoring two alarm comes on, it means missing label between cutter drum and glue roller
   
4. When you have chips of label on the cutting station, what can cause it?
   A) The knife is too out
   B) Excessive vacuum
   C) The cutting point on the cutter drum is not correct
   D) The knife is too short
   Having chips of label on the cutting station can be caused by having excessive vacuum
   
5. Servo drive signal malfunction on cutting unit means?
   A) The rotary cutter servo motor is not running due to restriction
   B) Servo amplifier is faulty
   C) The interrupt card on the servo motor is faulty
   D) Servo amplifier is not faulty
   Servo drive signal malfunction on cutting unit means Servo amplifier is faulty
   
6. If the label on the cutter drum is either too early or too late to the suction rail. How do you address it?
   A) Adjust the cutter drum
   B) Adjust the rotary cutter
   C) Adjust the vacuum cylinder
   D) None of the above
   The vacuum cylinder should be adjusted. The moment the technical trained personnel notice that the label at the cutter drum is either too early or too late he/she should adjust the vacuum cylinder
   
7. What are the possibility for glue splash?
   A) Too much glue at the roller
   B) Viscosity of the glue is too low
   C) Viscosity of the glue is too high
   D) Less glue at the roller
   Option A is wrong. The reason for it is that having too much glue at the roller does not matter if there will be glue splash, the only thing that matters most is the viscosity of the glue. If the viscosity is too low there will be label carryover because the glue will be too thick to be supplied by the glue roller, they can solve this by increasing the heat temperature at the bowl. If the viscosity is too high there will be glue splash because at that state the glue is lighter than it should be. The correct answer is C.
   
8. What is bottle gap detection?
   A) There is gap on the infeed conveyor
   B) There is gap on the infeed worm
   C) There is missing bottle at the carousel
   D) There is no gap on the infeed conveyor
   Bottle gap detection means there is a missing bottle at the carousel.
   
9. What is the function of the web guilder?
   A) To level the label going to the feed roller
   B) To remove electrostatic paralises
   C) To determine the right length of label to feed in
   D) None of the above
   The function of the web guilder is to level the label going to the feed roller
   
10. How do you set the encoder back to zero position if it is out of reference point?
    A) Mechanical zero position turning the encoder at its direction of rotation until there is a rising edge
    B) Mechanical zero position turning the encoder at its direction of rotation until there is a falling edge
    C) Mechanical zero position and calibrate the encoder
    D) None of the above
    
11. How is synchronization achieved between the carousel and labelling station?
    A) Incremental encoder
    B) Sensor
    C) Absolute en-dat encoder
    D) Servo motor resolver
    
12. What is the purpose of the infeed worm timing belt
    A) Synchronize the infeed conveyor with the machine
    B) Synchronize the infeed worm with the machine
    C) Synchronize the infeed worm with the labelling station
    D) None of the above
    To Synchronize the infeed worm with the machine
    
13. When the rotary cutter is at the reference point, what is the angular value?
    A) 180 degrees
    B) 90 degrees
    C) 110 degrees
    D) None of the above
    
14. The central head is hooking on the top cam and thereby causing an unusual noise, what are the possibilities?
    A) Wear and tear of the centering bolt and pressure spring
    B) Over tension of the pressure spring
    C) cam follower too tight
    D) Cam follower not too tight
    Wear and tear of the centering bolt and pressure spring
    
15. When the infeed clutch alarm is on
    A) The bearing has collapsed
    B) The belt is off
    C) The bearing has not collapsed
    D) The clutch has dis-engage
    The clutch has dis-engage
    
16. On krones machine why do you need to have oil on the cutter drum?
    A) To maintain the drum temperature against expansion
    B) To lubricate the inner bearings on the cutter drum
    C) Check through the sight glass to seethe bubbles of oil
    D) Option B and C
    
17. When the infeed clutch alarm is on
    A) The bearing has collapsed
    B) The clutch has dis-engage
    C) The belt has cut off
    D) All of the above
    The clutch has dis-engage
    
18. Basically quality assurance (QA) test are done on the labeller. One is the label wrapping quality and the other is?
    A) Fallen bottles
    B) Full bottle quality
    C) Full bottle label
    D) Full fallen bottles
    The other quality assurance (QA) test is full bottle label
    
19. Which encoder type is used to synchronize the rotary cutter with anvil bar of the cutter drum?
    A) On-dat absolute encoder
    B) Incremental encoder
    C) Servo motor resolver
    D) Sensor
    
20. What is the purpose of carousel timing belt?
    A) Synchronize the carousel with the infeed worm
    B) Synchronize the carousel with the Bottle plate
    C) Synchronize the carousel with the cylinder
    D) Turning the bottle seat 360 degrees
    
21. How many encoders do you have on the labelling machine?
    A) 6
    B) 2
    C) 8
    D) 4
    The labelling machine has 6 (but it varies in some type of manufacturers, some are 1 or 2)
    
22. What is the distance between the vacuum cylinder and the cutter drum?
    A) 0.6mm
    B) 0.2mm
    C) 2mm
    D) 6mm
    The distance between the vacuum cylinder and the cutter drum is 0.2mm
    
23. How is synchronization achieved between the carousel and the labelling station?
    A) Incremental encoder
    B) Absolute en-dat encoder
    C) Servo motor resolver
    D) All of the above
    
24. The signal from the encoder goes to the splitter from the splitter it splits it into three places which are?
    A) Vacuum cylinder, carousel and Main drive
    B) Discharge conveyor, carousel and vacuum cylinder
    C) Infeed conveyor, rotary cutter and main drive
    D) None of the above
    The three places it splits into are Vacuum cylinder, carousel and Main drive
    
25. In what situation should the machine be operated while the safety doors is open?
    A) During set-up
    B) During operation
    C) During shut down
    D) All of the above
    The machine safety doors should always be close expecially during running and start up. Some operators do close or open the safety doors during shut down anyway

1. Which of the factors listed below is not considered when selecting the types of conveyor chains and components to be used on conveyor system.
   A) The types of product to be handled
   B) Any specification of conveyor chains and components available for supply.
   C) Operating condition of the line
   D) The specification of the conveyor chains and components
   The types of product to be handled: Yes, one of the factors to be considered when selecting a conveyor is the type of the product to be run. On RGB( returnable glass bottles) line they make use of steel conveyor while the bead conveyor is used for can lines because of the type of product. Glass bottle are will spoil the bead conveyor and the stainless conveyor will cause scratch or dent on can if used.
   Operating condition of the line: the operating condition of conveyor on RGB lines should be 45⁰ centigrade or below it varies for Pet( polyethylene teraphthalate) lines
   Any specification of conveyor chains and components available for supply: These factor is not considered when choosing a conveyor. For instance, coca-cola bottling company will not want to know if a manufacturer have their required or specified conveyor or not, if they don’t have what they’re looking for they will request it from a manufacturer that have what they’re looking for e.g krones or sidel
   So therefore, the correct answer is B ( any specification of conveyor chains and components available for supply)
   
2. Split sprocket are mostly referred to one piece solid sprocket because
   A) They are more stable
   B) They are more cheaper
   C) They are more hygienic
   D) They are easier to install, maintain and inspect
   They are easier to install, maintain and inspect
   
3. Listed below are benefits derived from proper and thorough cleaning of conveyor systems except
   A) Increased line availability
   B) Optimized line efficiency
   C) Increased number of line stoppages
   D) Apreciable reduction in maintenance cost
   Increased line availability: No matter how old a line is it will continue to produce optimally as soon as the trained personnel is properly maintaining that machine adequately.
   Optimized line efficiency: The efficiency of a line could be increased due to meticulous care of the conveyor system.
   Increased number of line stoppages: This is not part of the benefits of properly and thoroughly cleaning the conveyor system
   Appreciable reduction in maintenance cost: If a line is properly maintained the company has no reason to repair or replace the conveyor hereby reducing the cost of maintenance. Some of our lines conveyor or parts cost more than millions so a preventive maintenance will result to little or no cost of maintenance.
   The correct answer is C(increased number of line stoppages)
   
4. Listed below are reasons why thorough cleaning of conveyor systems is necessary except
   A) To keep bacteria situation of the conveyor under control
   B) To optimize the service life of conveyor chains and components
   C) To increase the speed of the conveyors on the conveyor system
   D) To keep the friction level of the line low
   To keep bacteria situation of the conveyor under control: Meticulous care of the conveyor will prevent bacteria or contamination from entering the product.
   To optimize the service life of conveyor chains and components: How old a line or machine is doesn’t matter how optimally it will function as soon as the trained personnelis giving the machine proper maintenance
   To increase the speed of the conveyors on the conveyor system: Thorough clean of conveyor can’t increase the speed of the conveyor. The speed of the conveyor is determined by the speed of the machine operated at that particular time.
   To keep the friction level of the line low: There will be no resistance or restriction on the part of the conveyor system in order to run the line efficiently.
   The correct answer is C ( to increase the speed of the conveyors on the conveyor system)
   
5. One of the stakeholders listed below is not involved in cleaning of conveyor systems
   A) Line managers and operators
   B) consumer of products
   C) conveyor line designer and manufacturer
   D) Manufacturers of conveyor chains and components
   Consumer of products: The consumers aren’t allowed to enter the line except for business matters talkless of cleaning or operating the machine.
   
6. Chain elongation is mainly caused by
   A) Wear around the chain hinge
   B) Pull in the chain hinge
   C) Badly worn chain pin
   D) Badly worn chain plate
   It is mainly caused by badly worn chain pin
   
7. Which of the tools below can be used to inspect the gap between sprocket and shaft in order to determine the level of wear of sprocket bore.
   A) Measuring tape
   B) Feeler gauge
   C) Vernier calliper
   D) Spring scale
   The feeler gauge can be used to inspect the gap between sprocket and shaft in order to determine the level of wear of sprocket bore.
   
8. Which of the conveyor failures listed below will not require bearing replacement as a possible remedy.
   A) Excessive vibrations from bearings during operation
   B) Badly worn and elongated conveyor chains
   C) Excessive noise from bearing during operation
   D) Visible signs of fatigue and cracks on the cage and housing
   All of the following will cause it but a minimum of excessive vibrations from bearings during operation cannot cause change of bearing
   
9. One of the following is not part of the conveyor
   A) Wear strip
   B) Chain guide
   C) Roller ball
   D) Idler roller
   The wear strip, chain guide and idler roller are part of the conveyor but roller ball can be only found on the filler machine
   
10. Why is it important that the feet of the conveyor are on levelled ground?
    A) For rigidity
    B) For weight balancing
    C) All of the above
    D) Not for rigidity
    The feet of the conveyor are on levelled ground because of both rigidity an weight balancing. The weight of the product must be balanced for easy passage of the product and must be rigid to avoid fallen product
    
11. The correct way to split a roller chain is to split the chain at the master link
    A) TRUE
    B) FALSE
    Yes, it is true. The master link is used to join the moving part of the conveyor to the other part of the conveyor for easy rotation of the conveyor. So to split the roller chain you must split the chain at the master link.
    
12. A damage return roller can cause damage to;
    A) All of the above
    B) seizure of the roller
    C) Increased downtime
    D) Slat chain
    If a return roller is damage it can cause downtime, stoppage of the roller and damage to the slat chain connected to it. All of the above is the preferable answer
    
13. Lubrication of the conveyor at the flange bearing is through the _______
    A) Opening
    B) Top
    C) Nipple
    D) Mouth
    The bearing of the conveyor can only be lubricated through the nibble.
    
14. The following are signs of properly maintained conveyor system
    A) All of the following
    B) The slat chain must be replaced
    C) The collapsed bearing must be replace correctly
    D) The tension on the drive chain must be set correctly
    All of the above are signs of properly maintainance of the conveyor
    
15. Is it necessary that the conveyor system is level at all times;
    A) To prevent slack and ensure adequate tensioning of the conveyor and also to prevent bottles falling over and causing breakages on the line
    B) To prevent the driving motor from carrying heavy loads
    C) To prevent the conveyor from over speeding during operation
    D) To improve the running time of the conveyor line
    Yes, to prevent slack and ensure adequate tensioning of the conveyor and also to prevent bottles falling over and causing breakages on the line.
    
16. The main difference between a straight tab and flexible tab conveyor slat band is;
    A) The width
    B) The length
    C) The angle at the edge of the slat
    D) None of the above
    The main difference between a straight tab and flexible tab conveyor slat band is the angle at the edge of the slat. One of the tab angle is very close while the other is quite open
    
17. These are part of the modern day conveyor except
    A) Sprocket
    B) Idler shaft
    C) Motor
    D) Pulley
    You can’t see a pulley in a modern day beverage and food company line or machine
    
18. Which of these is not an appropriate check for conveyor systems
    A) Check sprocket tooth wear
    B) Check chain tension
    C) Check sustainability of hammer
    D) Check chain wear
    The other checks are okay but checking suitability of hammer seems useless here. Why should you check for the fitness of hammer why doing critical check on the conveyor?
    
19. Before any form of maintenance must be carried out on the conveyor you must do one of the following
    A) All of the following
    B) Shut down safely
    C) Main power supply isolated
    D) Empty the conveyor
    I know you want to say empty the conveyor, but you’ve to ask yourself if it is possible to correct or do any maintenance on a machine that is still running. So you have to first, empty the conveyor then shut down the machine then after isolate the main power supply in order to avoid any other personnel from starting the machine
    
20. Temperature of the motor driving the shaft of the conveyor motor must not exceed
    A) 45 degree centigrade
    B) 50 degree centigrade
    C) 55 degree centigrade
    D) 60 degree centigrade
    Temperature of the motor driving the shaft of the conveyor motor must not exceed 45 degree centigrade
    
21. In removing a slat chain the following is a required tools except one
    A) Appropriate pin punch
    B) Spirit level
    C) Hammer
    D) Appropriate screw driver
    If you have been on the line before you would have seen the operator/trained personnel or the engineer in charge using appropriate pin punch, hammer and screw driver but plumb or spirit level used by mostly bricklayers aren’t the required tools used in removing a slat chain.
    
22. It is ideal to have the master link of drive chain face inward instead of outward
    A) TRUE
    B) FALSE
    True, it is position inward so as to prevent it from being exposed to dangers likely from the loads, moving on the conveyor

1. A frequency determining circuit in an L-C sinewave oscillator consist of a high Q inductance L = 200μH in parallel with a capacitor of C = 450pF. Determine the frequency range of the oscillator if this capacitor, can be varied between 20pF-150pF.

Solution
Inductance, L = 200μH
= 200 × 10–⁶H
Capacitance, C = 450pF
= 450 × 10–¹²F.
LC = Inductance × Capacitance
200 × 10–⁶H × 450 × 10–¹²F = 9 × 10–¹⁴
Find the root of LC, √(LC) = 3 × 10–⁷

Therefore fo = 1/[2π√(LC)] = 1/[2π × 3 × 10–⁷]= 1/[2 × 3.142 × 3 × 10–⁷]= 1/0.0000018852
= 530447.7Hz
Approximately, = 530.4KHz

Continuation
When the variable capacitor C1 is connected in parallel with the circuit, the total capacitance in parallel with the inductor is increased to C+ C1, thus the corresponding oscillator frequency changes to

2. The resonant circuit of a tuned-collector oscillator has a resonant frequency of 5MHz if the value of the capacitance is increased by 50%. Calculate the new resonant frequency.

SOLUTION
f_o= 1/[2π√(LC)] Hz ………………………….. (1)
5 × 10⁶ = fo = 1/2π√LC ………………………. (2)
fo = 1/2π√L×1.5C …………………………….. (3)
Divide equation (3) by equation (2)
f_o/5×10⁶, = 1/√1.5 or f_o= 4.08MHz

3. A certain X-cut Quartz crystal resonate at 450KHz. It has an equivalent inductance of 4.2H and an equivalent capacitance of 0.0297pF. If its equivalent resistance to 600ohms, calculate Q factor.

Solution
Q = wL/R =( wavelength × Length, L)/resistance
Wavelength = 2πF
Q = 2πFL/R = (2×3.142×450,000×4.2)/600
11,876,760/600 = 19,794.6

4. A tuned-collector oscillator has fixed inductance of 100μH and has to be tuneable over the frequency band of 500KHz to 1500KHz. Find the range of the variable capacitor to be used.

Solution
Parameters given, inductance,L = 100μF ;= 100×10–⁶F

Frequency band = 500KHz – 1500KHz

Resonant frequency is given by;

f_o=(oscillator frequency) = 1÷2π√(LC) or 1/2π√(LC)

C = 1 ÷ 4π2f02L or 1/4π2f02L

Where L and C refer to the tuned circuit, therefore when f_o= 500KHz

C = 1/4π2 × (500 × 10³)² × 100 × 10–⁶

= 1015pF

f_o= 500KHz

C = 1/4π2 × (1500 × 10³)² × 100 × 10–⁶

= 113pF

The range of the variable capacitor to be used is = 113 – 1015pF

A string of suspension insulator consist of 3-units, the capacitance between each link pins to earth is one-sixth of the self-capacitance of the unit. If the maximum peak voltage per unit is not to exceed 20kv. Find the greatest working voltage and efficiency of the spring.

V = V1 + V2 + V3; = V1 + V2 + 20
Applying kcl(Kirchhoff’s voltage law) to NODE A
i3 + i1 + ic1
WC2V2 = WC1V1 + WCV1
WMCV3 = WMCV2 + WC(V1 + V2)
MV2 = MV1 + V1
MV2 = 7V1
M = C1/C ; C1 ÷ 1/6C1 = 6
6V2 = 7V1
V2 = 7/6V1

V3 = 20kv

AT NODE B

V2 = 7V1/6
7(13)/6 kv
= 15.2kv; approximately 15kv

Maximum voltage of the spring

Maximum efficiency of the spring

Efficiency = V ÷ (n×V3) × 100
= (48kv) ÷ (3×20kv) × 100
48/60 × 100 = 80%

What is an Oscillator?

The oscillator is a mechanical or electronic device and the working principle of the oscillator is, the periodic change between the two things depends on the changes in the energy. The oscillations are used in radios, watches, metal detectors, and in many other devices.

The oscillator converts the DC (direct current) from the power supply to an  AC (alternating current),  used in many electronic devices. The signal used in the oscillator is a sine wave & the square wave. The best examples of an oscillator are, the signals are broadcasted by the television transmitter and radio, CLKs which are used in the computers and also in the video games.

The oscillator works on the principle of oscillation and it is a mechanical or electronic device. The periodic variation between the two things is based on the changes in energy. The oscillations are used in watches, radios, metal detectors, and many other devices that use the oscillators.

Principle of Oscillators

The oscillator converts the direct current from the power supply to an alternating current and they are used in many electronic devices. The signals used in the oscillators are a sine wave and the square wave. Some of the examples are the signals are broadcasted by the radio and television transmitter, clocks which are used in computers and in video games.

Types of Oscillator Circuits

There are two types of oscillator circuits available they are linear and nonlinear oscillators. The linear oscillators give the sinusoidal input. The linear oscillators consist of a mass m and its force in the linear equilibrium. By applying the hook’s low the spring creates the force that i9s in linear for small displacements.

The different types of oscillator circuits are mentioned below and some of them are explained.

• Armstrong Oscillator
• Crystal Oscillator
• Hartley oscillator
• RC Phase Shift Oscillator
• Colpitts Oscillators
• Cross-Coupled Oscillator
• Relaxation oscillator
• Meissner Oscillator
• Phase shift oscillator
• Phase Shift Oscillator
• Wine Bridge Oscillator
• Sawtooth Voltage-Controlled Oscillator (VCO)

1. The Wien-Bridge Oscillator:One type of sinusoidal feedback oscillator is the Wien-bridge oscillator. A fundamental part of the Wien-bridge oscillator is a lead-lag circuit like that and C1 together form the lag portion of the circuit; R2 and C2 form the lead portion. The operation of this lead-lag circuit is as follows. At lower frequencies, the lead circuit dominates due to the high reactance of C 2 . As the frequency increases, X C2 decreases, thus allowing the output voltage to increase. At some specified frequency, the response of the lag circuit takes over, and the decreasing value of XCI causes the output voltage to decrease. The response curve for the lead-lag circuit shown in Figure 10.1(b) indicates that the output voltage peaks at a frequency called the resonant frequency,!,. At this point. the attenuation (Vout/Vin) of the circuit is 1/3 if R1 = R2 and XC1 = X C2 as stated by the following equation

A Wien bridge oscillator is a type of electronic oscillator that generates sine waves. It can generate a large range of frequencies. The oscillator is based on a bridge circuit originally developed by Max Wien in 1891 for the measurement of impedances. The bridge comprises four resistors and two capacitors.The oscillator can also be viewed as a positive gain amplifier combined with a band pass filter that provides positive feedback. Automatic gain control, intentional non-linearity and incidental non-linearity limit the output amplitude in various implementations of the oscillator.

         To summarize, the lead-lag circuit in the Wien-bridge oscillator has a resonant frequency, at which the phase shift through the circuit is 0 0 and the attenuation is 1/3.  Below, the lead circuit dominates and the output leads the input. Above fr, the lag circuit dominates and the output lags the input.  

The Basic Circuit The lead-lag circuit is used in the positive feedback loop of an op-amp, as shown below A voltage divider is used in the negative feedback loop.
Wien-bridge oscillator circuit can be viewed as a non-inverting amplifier configuration with the input signal fed back from the output through the lead-lag circuit. Recall that the closed-loop gain of the amplifier is determined by the voltage divider.

2. The Phase-Shift Oscillator

Phase-shift oscillator

3. The Colpitts Oscillator:

One basic type of resonant circuit feedback oscillator is the Colpitts, named after its inventor-as are most of the others we cover here. As shown in Figure 11.4, this type of oscillator uses an LC circuit in the feedback loop to provide the necessary phase shift and to act as a resonant filter that passes only the desired frequency of oscillation.

A crystal oscillator is an electronic oscillator circuit that is used for the mechanical resonance of a vibrating crystal of piezoelectric material. It will create an electrical signal with a given frequency. This frequency is commonly used to keep track of time for example wristwatches are used in digital integrated circuits to provide a stable clock signal and also used to stabilize frequencies for radio transmitters and receivers.

Loading Effects on the Frequency of Oscillation As indicated in Figure 12.1, the input impedance of the amplifier acts as a load on the resonant feedback circuit and reduces the Q of the circuit. Recall from your study of resonance that the resonant frequency of a parallel resonant circuit depends on the Q, according to the following formula:
As a rule of thumb, for a Q greater than 10, the frequency is approximately TLC  21 ,as stated in Equation 16-5. When Q is less than 10, however, fr, is reduced significantly.
Figure 12.1 Zin of the amplifier loads the feedback circuit

A FET can be used in place of a BJT, as shown in Figure 12.2, to minimize the loading effect of the transistor’s input impedance. Recall that FETs have much higher input impedances than do bipolar junction transistors. Also, when an external load is connected to the oscillator output, as shown in Figure l2.3(a),fr, may decrease, again because of a reduction in Q. This happens if the load resistance is too small. In some cases, one way to eliminate the effects of a load resistance is by transformer coupling.

4. The Hartley Oscillator

5. The quart crystal Oscillators:

The most stable and accurate type of feedback oscillator uses a piezoelectric crystal in the feedback loop to control the frequency. 3.9.1The Piezoelectric Effect Quartz is one type of crystalline substance found in nature that exhibits a property called the piezoelectric effect. When a changing mechanical stress is applied across the crystal to cause it to vibrate, a voltage develops at the frequency of mechanical vibration. Conversely, when an ac voltage is applied across the crystal, it vibrates at the frequency of the applied voltage. The greatest vibration occurs at the crystal’s natural resonant frequency, which is determined by the physical dimensions and by the way the crystal is cut. Crystals used in electronic applications typically consist of a quartz wafer mounted between two electrodes and enclosed in a protective “can” as shown in Figure 13.2(a) and (b). A schematic symbol for a crystal is shown in Figure 13.2(c), and an equivalent RLC circuit for the crystal appears in Figure 13.2(d). As you can see, the crystal’s equivalent circuit is a series-parallel RLC circuit and can operate in either series resonance or parallel resonance. At the series resonant frequency, the inductive reactance is cancelled by the reactance of Cs. The remaining series resistor, Rs, determines the impedance of the crystal. Parallel resonance occurs when the inductive reactance and the reactance of the parallel capacitance, Cm are equal. The parallel resonant frequency is usually at least I kHz higher than the series resonant frequency.

A quartz crystal

6. Crystal oscillator:

A great advantage of the crystal is that it exhibits a very high Q (Qs with values of several thousand are typical). An oscillator that uses a crystal as a series resonant tank circuit is shown in Figure 13.3(a). The impedance of the crystal is minimum at the series resonant frequency, thus providing maximum feedback. The crystal tuning capacitor, Cc, is used to “fine tune” the oscillator frequency by “pulling” the resonant frequency of the crystal slightly up or down.

A modified Colpitts configuration is shown in Figure 13.3(b) with a crystal acting as a parallel resonant tank circuit. The impedance of the crystal is maximum at parallel resonance, thus developing the maximum voltage across the capacitors. The voltage across C1 is fed back to the input.
Modes of oscillation in the Crystal Piezoelectric crystals can oscillate in either of two modes-fundamental or overtone. The fundamental frequency of a crystal is the lowest frequency at which it is naturally resonant. The fundamental frequency depend on the crystal’s mechanical dimensions, type of cut, and other factors, and is inversely proportional to the thickness of the crystal slab. Because a slab of crystal cannot be cut too thin without fracturing, there is an upper limit on the fundamental frequency. For most crystals, this upper limit is less than 20 MHz. For higher frequencies, the crystal must be operated in the overtone mode. Overtones are approximate integer multiples of the fundamental frequency. The overtone frequencies are usually, but not always, odd multiples (3, 5, 7, . . . ) of the fundamental.

7. Relaxation oscillator:

The second major category of oscillators is the relaxation oscillator. Relaxation oscillators use an RC timing circuit and a device that changes state to generate a periodic waveform. In this section, you will learn about several circuits that are used to produce non sinusoidal waveforms.

8. A Sawtooth Voltage-Controlled Oscillator (VCO)

The voltage-controlled oscillator (VCO) is a relaxation oscillator whose frequency can be changed by a variable dc control voltage. VCOs can be either sinusoidal or non sinusoidal. One way to build a sawtooth VCO is with an op-amp integrator that uses a switching device (PUT) in parallel with the feedback capacitor to terminate each ramp at a prescribed level and effectively “reset” the circuit. Figure 16-31(a) shows the implementation. As you learned in Chapter 1 I, the PUT is a programmable unijunction transistor with an anode, a cathode, and a gate terminal. The gate is always biased positively with respect to the cathode. When the anode voltage exceeds the gate voltage by approximately 0.7 V, the PUT turns on and acts as a forward-biased diode. When the anode voltage falls below this level, the PUT turns off. Also, the current must be above the holding value to maintain conduction. The operation of the sawtooth VCO begins when the negative dc input voltage, – V IN , produces a positive-going ramp on the output. During the time that the ramp is increasing, the circuit acts as a regular integrator. The PUT triggers on when the output ramp (at the anode) exceeds the gate voltage by 0.7 V The gate is set to the approximate desired sawtooth peak voltage. When the PUT turns on, the capacitor rapidly discharges, as shown in Figure l6-31(b). The capacitor does not discharge completely to zero because of the PUT’s forward voltage. V F . Discharge continues until the PUT current falls below the holding value. At this point, the PUT turns off and the capacitor begins to charge again, thus generating a new output ramp. The cycle continually repeats, and the resulting output is a repetitive sawtooth waveform, as shown. The sawtooth amplitude and period can be adjusted by varying the PUT gate voltage.

The frequency of oscillation is determined by the RiC time constant of the integrator and the peak voltage set by the PUT. Recall that the charging rate of a capacitor is VIN/RiC. The time it takes a capacitor to charge from V F to V p is the period, T, of the sawtooth waveform (neglecting the rapid discharge time).

After completing this section, you should be able to · Describe and analyze the basic operation of relaxation oscillators. Discuss the operation of basic triangular-wave oscillators . Discuss the operation of a voltage-controlled oscillator (VCO) . Discuss the operation of a square-wave relaxation oscillator

9. The Armstrong oscillator

The Armstrong oscillator is an LC electronic oscillator and to generate this oscillator we are using the inductor and the capacitor. In 9012 the US engineer Edwin Armstrong has invented the Armstrong oscillator and it was the first oscillator circuit and also in1913 this oscillator was used in the first vacuum tube by the Alexander Meissner who as an Austrian engineer.
The Armstrong oscillator is known as the tickler oscillator because of the individual features of the feedback signal should produce the oscillations are magnetically coupled to the tank indicator. The Armstrong oscillator is also called as the meissner oscillator or tickler oscillator.

10. The dynatron oscillator

The dynatron oscillator, invented in 1918 by Albert Hull at General Electric, is an obsolete vacuum tube electronic oscillator circuit which uses a negative resistance characteristic in electrode vacuum tubes, caused by a process called secondary emission. It was the first negative resistance vacuum tube oscillator. The dynatron oscillator circuit was used to a limited extent as beat frequency oscillators (BFOs), and local oscillators in vacuum tube radio receivers as well as in scientific and test equipment from the 1920s to the 1940s but became obsolete around World war 2 due to the variability of secondary emission in tubes.

A 500/200v single phase transformer has primary resistance of 0.5Ω and reactance of 3.7Ω, while the secondary resistance and reactance are 0.03Ω and 0.25Ω respectively. Compute the equivalent values of resistance, reactance and impedance referred to;
I. the primary
II. the secondary

Equivalent resistance

Finding equivalent reactance( values of reactance)
Xe( equivalent reactance) = X1 + X2 (V1/V2)²
Xe = 3.7+ 0.25)500/200)²
Xe =3.7+ 0.25(2.5)²
Xe = 3.7+ 0.25(6.25)
Xe = 3.7 + 1.56
Xe = 5.26Ω

Impedance referred to the primary ( values of impedance referred to primary and secondary)
Z1² = R1² + X1²
Z1 = √[R1² + X1²]Z1 = √[0.5² + 3.7²]Z1 = √[0.25 + 13.69]Z1 = √[13.94]Z1 = 3.75Ω

Impedance referred to the secondary
Z2² = R2² + X2²
Z2 = √[R2² + X2²]Z2 = √[0.03² + 0.25²]Z2 = √[0.0009+ 0.063]Z2 = √[0.0639]Z2 = 0.25Ω

MACHINE (WORK 1)

(A) M.A = F.R, M.A = load/effort or output force/input force
Where F.R = force ratio
(B) Velocity ratio = distance moved by effort/ distance moved by load = e/L
(C) Efficiency = M.A/V.R × 100%
Or
Efficiency = work output/work input × 100%
EXAMPLE 1
A machine has an efficiency of 80%, if the machine is required to overcome a load of 60N with a force of 40N, calculate its velocity ratio. Neco 2003
Solution
Efficiency = 80%, Load = 60N, Effort = 40N, V.R =?
To get the velocity ratio we’ve to first find mechanical advantage (M.A)
Mechanic advantage(M.A) = Load/ effort
60/40 = 1.5
Efficiency = M.A/V.R × 100%, 80 = 1.5/V.R × 100
V.R = (1.5 × 100)/80, = 1.875

EXAMPLE 2

A machine has an efficiency of 60%, if the machine is required to overcome a load of 30N with a force of 20N;
(I) calculate the mechanical advantage
(II) velocity ratio
Solution
Efficiency = 60%, load= 30N, effort = 20N
Mechanical advantage (M.A) = Load/effort; = 30/20
M.A = 1.5
Efficiency = M.A/V.R × 100%, 60 = 1.5/V.R × 100
V.R = (1.5 × 100)/80, = 2.5

EXAMPLE 3

A machine has a velocity ratio of 6 and an efficiency of 75%. Calculate the effort needed to raise a load of 90N.
Solution
Velocity ratio (V.R) = 6, Efficiency = 75%, load = 90N, effort = ?
First find mechanical advantage (M.A),
M.A = Load/Effort
Efficiency = M.A/V.R × 100%, 75 = M.A/6 × 100
M.A = (6×75)÷100; = 4.5
Calculate effort
M.A = Load/Effort; 4.5 = 90/Effort
Effort = 20N
Another formula for solving efficiency, work 2

Efficiency = (Load × distance moved by load) ÷ (effort × distance moved by effort) × 100%
Or effort = work output/work input × 100%

EXAMPLE 4

A block and tackle system is used to lift a load of 20N through a height of 10m. If the efficiency of the system is 40% how much work is done against friction.
Work done = work input = effort × distance moved by effort
Now using,
Efficiency = work output/ work input × 100%
Work output = load × distance moved by load
Where
L = 20, distance (h) = 10m, Efficiency = 40%, work output = ?
Efficiency = (Load × distance moved by load) ÷ (work input) × 100%
40 = (20×10)÷(work input) × 100
Work input = (20×10×100)÷40
20000/40 = 500N
How much work is done against friction?
Work output = Load × distance moved by load; 20×10 = 200N
Work input – work output = 500 – 200; = 300N

Another formula, work 3

Velocity ratio (V.R) = numbers of poles supporting the pulley
Example 5
A block and tackle system has six(6) pulley. A force of 50N applied to it lifts a load of weight (W). If the efficiency is 40% calculate the value of w.
Solution
Velocity ratio (V.R) = Number of pulley = 6, effort (force) = 50N, Efficiency = 40%, weight,w(load) = ?
Efficiency = M.A/V.R × 100%
40 = M.A/6 × 100%
M.A = (40×6)/100
M.A = 2.4
Now using,
M.A = Load/Effort; 2.4 = Load/50
Weight (load) = 50×2.4; 120N
Another formula, inclined plane (work 4)
V.R = distance moved by load / distance moved by effort
Or Length of inclined plane/height of inclined plane
Sinø = opposite/hypotenuse = H/L
Rearranging, 1/sin∅ = L/H
Therefore V.R; = L/H = 1/sinø

Example 6

An inclined plane of angle 15⁰ is used to raise a load of 4500N, through a height of 2m if the plane is 75% efficient, calculate;
(I) velocity ratio of the plane
(II) work done on the load
Solution
Angle of inclination (Ø) = 15⁰, load = 4500N, H = 2m, efficiency = 75%
V.R = 1/sinø; 1/sin15
= 3.86
Work done = work input
Using,
Efficiency = (work output/work input) × 100%
Work input = (work output/Efficiency) × 100%
Work input = (Load × height of plane/ efficiency) × 100%
(4500×2×100)/75 = 12000J

Another formula, work 4

The wheel and axle
Radius of the wheel (R) , radius of the axle (r)
Work input(work done by effort) = work done by load
Effort × distance moved by effort = load × distance moved by load
Or effort × circumference of wheel = load × circumference of axle
E × 2πR = L ×2πr
Therefore, velocity ratio (V.R) = distance moved by effort/distance moved by load
V.R = 2πR/2πr
Efficiency = (load/effort × 2πr/2πR) × 100%
(L/E × r/R) × 100%

Example 7

A wheel and axle is used to raise a load of 500N by the application of an effort 250N, if the radii of the wheel and axle are 0.4cm and 0.1cm respectively. The efficiency of the machine will be?
Solution
Load = 500N, effort = 250N, radius of the wheel (R) = 0.4cm, radius of the axle (r) = 0.1cm
Using
Efficiency = (L/E × r/R) × 100
E = 500/250 × 0.1/0.4 × 100
E = (500×0.1×100) / (250×0.4)
5000/100 = 50%

With the aid of a block diagram explain the working principle of a gas turbine power plant

A gas turbine power plant iss the type of generating station that uses gas turbine as the prime over for the generation of electrical energy. The air combustion chamber where heat is added to air, thus raising its temperature. Heat is added to the compressed air either by burning fuel in the chamber or by the use of air heaters. The hot and pressured air from the combustion chamber is then passed to the has turbines when it expands and does the mechanical work. The gas turbine drives the alternator which converts mechanical energy into electrical energy.

B. With the aid of a block diagram explain the working principle of a steam power plant

The steam power station is the type of generating power station that converts heat energy to electrical energy. The steam is produced in the boiler by utilising the heat of coal combustion. The steam is then expand in the prime mover (i.e the steam turbine) and is condensed in a condenser to be fed in the boiler again. The steam turbine drives the alternator which converts mechanical energy into electrical energy.

WHAT ARE THE SIX CAUSES OF ACCIDENT ON LINE ONE(1) TO LINE EIGHTEEN (18)

1. Poor house keeping: not properly arranging the line after production, speels all over the plants, e.t.c can cause accident on the plants.
2. Falling hazard: Falling hazard include stuffs like a falling ladder, falling gadgets, falling gas cylinder or any other equipment that can fall on a person, that has the potential of causing death, injury or damage to someone.
3. Wrong lifting: powered tools not held well or too heavy. Even wrong usage of equipment or tools can be an hazard.

What are the safety behaviours one must observe when operating the machine

1. Follow the employer’s operating instructions concerning machine operation
2. Read the current operating manual before doing any work on the machine.
3. Observe all applicable safety regulations. Take all necessary safety precautions to prevent hazardous situations when operating the machine/system.
4. When you turn ON the machine, make sure that no one else except you is near the machine or in the danger zone, particularly when jogging the machines while the guard doors are open.
5. Access danger zones ( zones which are behind protective devices) only through entrances designated by the manufacturer and only after having properly/ shut down the machine and having loaded it
   This is to prevent it from being turned ON again
6. Before starting work, check the safety devices and the machine for visible defects
7. If the defects pose an operational safety hazard, do not operate the machine respectively switch it off
8. If the machine has any defects, especially those which affects safety, inform your superior, and when changing shifts also inform the person who takes over the shifts
9. Never actuate or tamper with control components and monitoring device, etc….if you’re unauthorised or do not know how they work.
10. Never wear jewellery (rings, bracelet, etc) which could get caught in machine parts. Long hair should be tucked under an hair net.
11. Never allow the machine to run unattended.
12. Wear a fall arrester when working in great heights.

HAZARDS AT THE MACHINE: infeed

1. Risk of injury due to cullet (serrations, eye injuries)
2. Risk of injury due to bottle movement ( crushing hazard)
3. Risk of injury due to unauthorised climbing onto the infeed table
4. Risk of injury due to noise ( hearing impediment)
5. Risk of infection due to microorganisms

HAZARDS AT THE MACHINE: liquids

1. Risk of injuries due to chemicals (skin/eye injuries)
2. Risk of injury due to high temperatures ( the temperature is above 45⁰c in many zones of the bottle washer)
3. Risk of infection due to microorganisms.
4. Risk of injury due to slipping on wet surfaces
5. Risk of injury due to electricity (when electronic components are defective in combination with moisture)
   Also as a technician you should ‘observe the safety instructions of the chemical supplier

HAZARDS AT THE MACHINE: caustic area

1. Risk of injury due to chemical burning (skin/eye injuries)
2. Risk of injury due to high temperatures ( the caustic temperature is around 80⁰c)
3. Risk of injury due to contact with non-insulated machine parts (e.g: heating valves, heating piping)
4. Risk of injury due to hot vapours (skin/eye/lung injuries)
5. Risk of injury due to label press (injury to hand)
6. Risk of injury due to label conveyors (injury to hand)
7. Risk of injury due to slipping ( caustic is slippery)
8. Risk of explosion due to hydrogen gas(H2) – if materials with tin foil are fed into the machine the aluminium decomposes in the caustic solution and releases hydrogen gas. This gas combines with oxygen in the air to form an explosive mixture which in even a small concentration can easily be ignited.

HAZARDS AT THE MACHINE: main drive

1. Risk of injury due to mechanical movement (crushing hazard)
2. Risk of injury due to adjustment work (jogg mode)
3. Risk of injury due to an automatic restart of the machine

HAZARDS AT THE MACHINE: discharge

1. Risk of injury due to cullet (serrations, eye injuries)
2. Risk of injury due to mechanical movement (crushing hazard)
3. Risk of injury due to noise (hearing impediment)
4. Risk of injury due to caustic remains in the container (caustic bottles, sealed bottles, which have been used for other than the intended purpose, e.g solvent solution and others)

HAZARDS AT THE MACHINE: extractions

1. Risk of injury to the eyes due to misguided spraying
2. Risk of injury due to chemical burning
3. Risk of injury due to heat (especially in the post caustic)
4. Risk of injury due to mechanical movement (crushing hazard especially with clock filter conveyors)

What is electrical installation: it is an electrical wiring of cabling or fixing electrical equipment and other accessories such as sockets, switches, chandelier, distribution board, lamp holder e.t.c on a building, office, company e.t.c

Types of electrical installation

1. Wiring diagram
2. Circuit diagram: they can be subdivided into two namely;
   I. Pictogram
   II. Schematic diagram
   WIRING DIAGRAM
   It is a specified convention representation of an electrical circuit that gives information about the relative position and arrangements of a device and terminal on a device. Also it helps in physical connection and layout of an electrical system or circuit.
   ADVANTAGES OF WIRING DIAGRAM
   1. It shows the component of the circuit at specified shapes.
   2. It shows the parts and the signal connection between the devices.
   3. It gives the information about relative position and arrangement and terminal on a device to help in building and services.
   CIRCUIT DIAGRAM
   Is also known as electrical diagram. It is a graphical representation of electrical circuits, it is widely used for circuit design, maintenance, construction of an electrical or electronic equipments. Circuit diagram can be divided into two;
   I. PICTOGRAM DIAGRAM: it shows realistic connection of an electrical components with wiring system without requiring any professional knowledge.
   II. SCHEMATIC DIAGRAM: It represent the elements of a system with abstract and graphic symbols instead of realistic picture. It focus more on comprehending and spreading information rather than doing physical operation.
   ADVANTAGES OF SCHEMATIC DIAGRAM
   1. It shows all the electronic parts
   2. It shows how they are interconnected
   3. It is easy to follow and understand
   DISADVANTAGE OF SCHEMATIC DIAGRAM
   1. It does not show high frequency critical part
   2. It does not show mechanical parts like heat sink
   3. It does not show parasitic components and led length

3 SINGLE PHASE TRANSFORMER CONNECTED INTO A STAR DELTA 3∅ GROUP

They are joined by means of common yokes, the top yoke 2, and the bottom yoke 3. The phase windings are arranged on the limbs and are connected into three phase circuit to make a 3∅ transformer.
The first part of the transformer is a 3∅(phase) star connected transformer. While the second part of the transformer is a 3∅(phase) delta connected transformer. Symbolised as ∆
The 3-∅ transformer is obtained by connecting the terminals of three single-phase transformer in such a way as to form a three-phase circuits.

1. Write short notes on the following electrical tests
   I. Short circuit test
   II. Open circuit test
   III. Efficiency of a transformer
   IV. Voltage regulation

A. SHORT CIRCUIT TEST: The secondary is short-circuited through a suitable ammeter, A2, While a lot voltage is applied to the primary and adjusted to circulate full-load current in the primary and secondary circuit iron losses is negligible and wattmeter reading is that of copper losses in the windings [ iron loss a (flux)² applied voltage which is small about 1/30 of V1]Constant Losses: The iron loss due to hysteresis and Eddy currents are constant at all loads because Flux variation between no load and full load is 2%-5%
Variable Losses: The copper loss depends on the load since variation of load from no load to full load is 100%.

B. OPEN-CIRCUIT TEST: The transformer is run at the rated voltage and frequency. The ammeter (A) gives the No-load current while the wattmeter in the primary circuit reads No-load losses i.e the iron losses [ I²R or copper loss is negligible on no load since it depends on primary current which is less than 5% of full load current at no load]The ratio of the voltmeter reading V1/V2 gives the ratio of the number of turns

C. EFFICIENCY OF A TRANSFORMER: Efficiency of a transformer is the ratio of output power to the input power.
Efficiency = output power/input power
Output power/(output power+losses) = input-losses/input power

D. VOLTAGE REGULATION: is defined as change in secondary terminal voltage from No-load to Full-load and is expressed as percentage of either No-load or the Full-load value.
Voltage regulation = (No-load voltage – Full load voltage)÷ (Full-load voltage)
Voltage regulation may be taken as the drop in secondary voltage as the secondary is loaded with the primary voltage being constant. This variation between no load and full load is normally not more than 1½ to 2%

COOLING METHODS OF A TRANSFORMER

1. Air cooling:
   AN – Ambient air as coolant with natural circulation by convection [ up to 1.5MVA] and special conditions such as mines
   AF – Forced air circulation
2. OIL IMMERSED, OIL COOLING:
   ONMAN- Natural oil circulation and natural air flow over the tank (tubes) up to 5MVA
   ONAF – Natural oil circulation with air blown (forced) on to the tank surface.
   OFAN – Oil is pumped round the system while natural air blows over tank. With this, high current densities can be used in the windings.
   OFAF – Forced oil – an air – circulation method used for transformer up to 300MVA and upward.
3. OIL – IMMERSED, WATER COOLING
   ONWF – Natural oil cooling of windings and water is forced through copper cooling coils mounted in the tank above the level of the transformer core, but below the oil surface.
   OFWF – Oil/water heat exchangers are external to the transformer and are pumped into it. Thus, the tank does not need to contain cooling oils and the tank is smaller.

REGULATED POWER SUPPLY

it is the terminal voltage that will remains almost constant regardless of the amount of current drawn from it.

1. TRANSFORMER: its job is either to step up or step down the a.c supply voltage to suit the requirements of the solid states electronics devices and circuit fed by the D.C power supply. It also provides isolation from the supply line.
2. RECTIFIER: It is a circuit which employs one or more diodes to convert a.c voltage into pulsating d.c voltage.
3. FILTER: The function of this circuit element is to remove the fluctuation or pulsations (called ripples) present into the output voltage supplied by the rectifier.
4. VOLTAGE REGULATOR: It main function is to keep the terminal voltage of the d.c supply constant even when (a) a.c input voltage to the transformer varies or (b) the load varies.

Using zener diode and transistor are used for voltage regulation purposes. It’s impossible to get 100% constant voltage but minor variations are acceptable for most of the jobs

CHAPTER ONE

INTRODUCTION
1.1 BACKGROUND OF STUDY
Electricity could be said to be one of the greatest inventions of man. This is because many other inventions and processes depend on it for proper functioning. The most common source of this important energy is the utility lines that come from hydroelectric power stations. However, the AC supply from utility lines is subject to power surges, voltage shortage, complete power failure and wide variations in the electric current frequency. The epileptic and unreliable power supply by the authority in Nigeria, especially in recent times, is a major issue of concern to every well-meaning Nigerian. The need for a constant supply of electricity has always been the priority of the power authority yet they cannot boast of supplying power constantly for a running day. Due to such, a need arose for the design and construction of the Uninterrupted Power Supply (UPS).
For ordinary household appliances such as incandescent lamps, heaters, fans and fridges, the common mains ac supply could be used casually, that is, without giving thought to its inherent shortcomings, because the performance of these appliances are seldom affected by power variations or interruptions. This is not the case with sophisticated and sensitive electronic instruments/equipment such as computers, medical equipment and telecommunication systems which require a stable and interruption free power supply.
Uninterruptible Power Supply (UPS) is an electrical apparatus that provides emergency power to a load when the input power source, typically mains power, fails. It provides near-instantaneous protection from input power interruptions, by supplying energy stored in batteries.  The on-battery runtime of most uninterruptible power sources is relatively short (only a few minutes) but sufficient to start a standby power source or properly shut down the protected equipment.
The energy crisis affecting small and medium scale industries and light household loads can effectively be addressed by devising methods of energy storage which could be used during short-period power outage or using a generator which is very costly to maintain. An absolute solution to energy demand can be achieved by adoption of renewable energy development especially the abduction of charge inverter.
    The inverter makes use of an energy source such as photovoltaic to be domestically and industrially relevant for use, as in short goes a long way to reduce the level of greenhouse gases in the atmosphere and alleviate this global warming on process. The photovoltaic power generation is reliable. It involve no moving parts and the operation and maintenance cost are very low (Coker and Ogungi, 2013).
Electricity generation is the first process in the delivery of electrical power to consumer. The other processes are electricity transmission and distribution. The importance of electricity generation was revealed when it became apparent that electricity generation was useful for producing heat, light and power for human needs.
An inverter converts the DC voltage to an AC voltage, In most cases, the input DC voltage is usually lower while the output AC is equal to the grid supply voltage of either 120 volts or 240 volts depending on the country.
The inverter may be built as standalone equipment for applications such as solar power or to work as a backup power supply from batteries which are charged separately.
The other configuration is when it is a part of a bigger circuit such as power supply unit or a UPS. In this case, the inverter input DC is from the rectifier mains AC in the UPS, while from either the rectifier AC in the UPS when there is power and from the batteries whenever there is a power failure.
There are different types of inverters based on the shape of the switching waveform. These have varying circuit configuration, efficiencies, advantages and disadvantages.
An inverter provides an AC voltage from DC power sources and is useful in powering electronics and electrical equipment rated at the AC mains voltages. In addition they are widely used in the switched mode power supplies inverting stages. The circuits are classified according to the switching technology and switch type, the waveform, the frequency and output waveform.

1.2    STATEMENT OF THE PROBLEM

Unexpected power disruption in homes, offices and industries could cause injuries, fatalities, serious business disruption or data loss. Of the myriad of devices, processes and systems which rely on AC power, computers are the most sensitive to power disturbances and failures. Interruptions in power supply may cause the contents of a memory to be lost or corrupted, the entire system to malfunction or fail, or even variety of components failures to occur, all of which not only result in inconvenience but also loss of money. The problems can be summarized thus:
I.    Unexpected power disruption could cause the malfunction of certain life support equipment used in hospitals which may result in injury or even death.
II.    In telecommunication and data centers, an unexpected power disruption could cause hardware malfunction, data loss or temporary closure of business, all of which incur greater expenses to the business owner.
III.    In homes and small offices, unexpected power disruption cause malfunction and memory loss in personal computers which result in loss of time, energy and money.
The power disruptions could be any of the following:
I.      Voltage spike or sustained over voltage.
II.      Momentary or sustained reduction in input voltage.
III.      Noise, defined as a high frequency transient or oscillation, usually injected into the line by nearby equipment.
IV.      Instability of the mains frequency.
V.      Harmonic distortion, defined as a departure from the ideal sinusoidal waveform expected on the line.

1.3    RESEARCH OBJECTIVE

The following are the main objective of this project,
To understand the appropriate circuit diagram for the construction.
To test the functionality of the constructed project.
A backup power supply system which is eco friendly
To provide a noiseless and weightless source of electricity supply.

1.4       CONTRIBUTION TO KNOWLEDGE

The project seeks to improve on the exiting power inverters and bring to forth features and upgrades such as;
The availability of low cost constant power source.
Low cost modified sine wave inverter to upgrade on the square wave inverter without increasing cost of production.
Low battery charging consumption.
Micro second automatic load transfer and switching to avoid computer from restarting.

1.5    LIMITATION OF THE PROJECT

Inverter has many varieties, but this project has been limited to the development and construction of 1kva inverter. The battery can only be charge through power supply which can at times reduce life span of the inverter if not properly charged.
    In spite of the base of construction of an inverter and its noiseless and pollution free nature unlike other alternative sources of the generator electricity, there is a need for charging and recharging the battery from time to time.

1.6    METHODOLOGY

To achieve the aim of this project, the following shall be carried out:
i.    Detailed analysis and dimensioning of the various components that makes up the UPS system.
ii.    Calculation of the necessary parameters so as to obtain the value of the various components used in the circuit design.
iii.    Purchase and testing of circuit components.
iv. Construction and testing of the device.

1.7    DEFINITION OF TERMS

Inverter: A power inverter, or inverter is a power electronic device or circuitry that changes Direct Current (DC) to Alternating Current (AC).
Battery: A container consist of one or more cells in which chemical energy is converted into electricity and used as a source of power
Electrical panel: An electronical distribution board that houses electrical circuit breaker is known as electrical panel. It is the main point which point at which electricity is distributed throughout a building, it is otherwise known as a breaker box or electrical cabinet.
Alternative current: An electric current which periodically reverses direction and charges its magnitudes continuously with time in contrast to direct current which flows only in one direction.
Electrical Power: Is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.
UPS: An uninterruptible power supply or Uninterruptible Power Source (UPS) is an electrical apparatus that provides emergency power to a load when the input power source or main power fails.
Volts: It is the amount of force required to drive a steady current in an electrical system. It is the S.I unit of voltages.
Watts: The watt is a standard unit of measuring power either by capacity or demand.

CHAPTER TWO

2.0 LITERATURE REVIEW
2.1 BRIEF OUTLINE OF THE CHAPTER
The chapter discusses the historical background of a commonly used inverter such as 1KVA inverter; it also covers the theories, relevant concept and works of the past researchers on the development and construction of an inverter.

2.2 HISTORICAL BACKGROUND OF THE STUDY

Origins of the Inverter David Prince probably coined the term inverter. It is unlikely that any living person can now, establish with certainty that Prince (or anyone else) was the originator of this commonly used engineering term. However, in 1925 Prince did publish an article in the GE Review titled The Inverter Elf. It conveys the idea of a rectifier except functioning in an inverted mode of operation, hence inverter. A current converter (stronzrichter) is thus a device for converting alternating to direct current or vice versa, or for converting alternating current of one frequency into alternating current of another frequency. By 1936, Princes inverter appeared in literature from all corners of the world, Europe and Japan among them. It was in common use in English technical publications or its equivalent word was used in other languages. In 1925, Prince defined inverter as the inverse of rectifier. In so doing, he depended upon his audience having a clear mental abstraction of rectifier and built upon their pre-existing concepts. The term rectifier was in common use for more than two decades prior to 1925. It was understood to mean any stationary apparatus or rotating commutator for transforming alternating into direct current. When operated to convert DC power to AC power, rotaries were dubbed inverted rotaries. The distinction between rectifier and converter was sometimes vague, perhaps even arbitrary, but often based on use of static or non-rotating versus rotating parts. The article explains how the rectifier circuit and inverted it, turning in direct current at one end and drawing out alternating current at the other. Use of the word inverted conveys the idea of turning something upside down. What was turned upside down? Clearly, he did not mean to invert the rectifier devices) or rectifier circuit; their orientation remains the same. Rather, he meant to invert the function or operation of the rectifier. That is why he said to draw in direct current and push out alternating current, to emphasize a new mode of operation. However, direction of direct current is not reversed. It is direct potential (voltage) at the rectifier terminals that is inverted or reversed. Because potential is reversed with current continuing in the same direction as before, the flow of electric power is also reversed or transferred from the DC system to the AC system. The inverse of rectification was not an obvious extension of prior art. It required several imaginative steps by Prince to bring his readers to comprehend conversion of electric current of one form (direct) to another form (alternating) Among those innovations was grid control of current conduction Prince was not the originator of that idea, but built upon it. Today, the IEEE dictionary similarly defines inverter (electric power) as a machine, device, or system that changes direct-current power to alternating-current power. Rectifier elements can be physical devices or circuit entities In either case, rectifier elements allow current to flow in only one direction, blocking its flow in the reverse direction (I e., diodes, thyristors).

2.3 THEORIES RELEVANT TO THE PROJECT

There has been numerous research carried out years back aimed at improving an inverter that is, achieving a cheap, portable, noiseless, pollution free means of converting D.C power to A.C in 1990, Lame Fox designed an inverter circuit consisting of two power transistors, connected in switching mode and is controlled by an oscillator from a D.C source (battery) to a 120V A.C output through a transformer secondary. But the limitation to the design of the circuit were very low current in the order of milliamps and poor efficiency.
Another circuit were designed and constructed, a D.C to A.C converter that yielded an output power of 6KVA, 220VAC and 50HZ with an efficiency of 93.5%. This solved the problem of low output and poor efficiency encountered by Lame Fox circuit. The design was constructed by Jacob in 1986.
The manufacturing company which produces an Uninterrupted Power Supply (UPS) designed an inverter circuit that gave an output of 4KVA, 270VAC, 50HZ and an efficiency of 95% in the year 2000. This was a huge development in the design of inverters and an uninterrupted power supply.
The only problem with the inverter is the cost which is very expensive compared to other types of inverter, that is (square wave and modified sine wave) of the same capacity.
In 2008, a student of electrical engineering department of the Federal Polytechnic, Bida designed and constructed a 200W inverter. The output power was very low with respect to the present day demand for energy.
Also in 2008, Flex More cyber café Federal Polytechnic installed 1KVA inverter to serve as a power backup for their computer.

2.3.1 TYPES OF INVERTER

There are three basic types of DC-AC converters: Square wave, Modified wave and Pure sine wave. The square wave is the simplest and cheapest type, but nowadays it is practically not used commercially because of low power quality. The modified sine wave topologies (which are actually modified square waves) provide square waves with some dead spots between positive and negative half-cycles. They are suitable for many electronic loads, although their THD (Total Harmonic Distortion) is about 25%.
Modified sine wave models are the most popular low-cost inverters on the consumer market today, particularly among car and domestic inverters. If you are buying a model whose description does not state that it is a pure Sine wave type, then most likely it is a modified one.
Note, output voltage waveform in conventional modified Sine wave DC-AC circuits has only two levels: zero or peak voltage of both polarities. By adding another voltage level, a designer can reduce THD typically from 25% to 6.5%. Periodically connecting the output to a specific voltage level with proper timing can produce a multiple-level waveform which is closer to sinusoidal than conventional modified sine wave. A Sine wave inverter produces output with low total harmonic distortion (normally below 3%). It is the most expensive type of AC power source, which is used when there is a need for clean sinusoidal output for sensitive devices such as medical equipment. Laser printer, stereos etc.
There are a number of topologies used in the inverter circuits. Cheap square wave circuits suitable primarily for hobbyists project may use just as push-pull converter with a step-up transformer. Most commercially manufactured models use a multi-stage concept. With such technique, first a switching pre-regulator (SMPS) steps up a voltage from an input source to another DC voltage corresponding to the peak value of the desired sinusoidal voltage. The output stage then generates an AC. This stage usually uses a full-bridge or half-bridge configuration. If a half-bridge is used, the DC-link voltage should be more than twice the peak of the generated output. Input to output galvanic isolation is provided by either a high-frequency transformer in the SMPS pre-regulator, or by a large low-frequency output transformer. If a low-frequency transformer is used, the sinusoidal voltage is generated on its primary side and transformed to the secondary side. The output can be controlled either in square-wave mode or in pulse width-modulated (PMW) mode. Sine wave circuit use PMW mode, in which he output voltage and frequency are controlled by varying the duty cycle of the high frequency pulses.
Chopped signal then passes through a low pass LC-filter to supply a clean sinusoidal output. Although such approach is more expensive, it is usually employed in the backup devices for home or business use, which require high quality of AC power.

2.3.2 STRUCTURE OF THE SYSTEM

The inverter is of two design; basic design and advance design.
2.3.2.1 Basic designs`
In one simplest inverter circuit, DC power is connected to a transformer through the center tap of the primary winding. A switch is rapidly switched back and forth to allow current to flow back to the DC source following two alternate paths through one end of the primary winding and then the other. The alternation of the direction of current in the primary winding of the transformer produces alternating current (AC) in the secondary circuit.
The electromechanical version of the switching device includes two stationary contacts and a spring supported moving contact. The spring holds the movable contact against one of the stationary contacts and an electromagnet pulls the movable contact to the opposite stationary contact. The current in the electromagnet is interrupted by the action of the switch so that the switch continually switches rapidly back and forth. This type of electromechanical inverter switch, called a vibrator or buzzer, was once used in vacuum tube automobile radios. A similar mechanism has been used in door bells, buzzes and tattoo guns. As they became available with adequate power ratings, transistors and various other types of semiconductor switches have been incorporated into inverter circuit designs.
2.3.2.2 Advanced design
There are many different power circuit topologies and control strategies used in inverter designs. Different design approaches address various issues that may be more or less important depending on the way that the inverter is intended to be used. The issue of waveform quality can be addressed in many ways. Capacitor and inductors can be used to filter the waveform. If the design includes a transformer or to both sides. Low-pass filters are applied to allow the fundamental component of the waveform to pass to the output while limiting the passage of the harmonic components. If the inverter is designed to provide power at a fixed frequency, a resonant filter can be used. For an adjustable frequency inverter, the filter must be tuned to a frequency that is above the maximum fundamental frequency.

2.3.1.1 POWER INVERTERS AND ITS WAVEFORMS

Inverters, besides coming in a wide variety of power capacities, are distinguished primary by the shape of the alternating current wave they produce. The three major waveforms are square-wave, modified sine-wave and true sine-wave. Almost all inverters reply on push pull class B amplifier but the wave of the power output largely depends on the type of oscillator used in the design. For example if an astable multi-vibrator is used as the oscillator in an inverter, the wave form at the output would be square wave because the multi-vibrator is a square wave oscillator.

            Fig.2.1 Types of inverters waveforms

2.3.1.2 Square Wave Inverter

Square wave inverters are largely obsolete, as the waveform shape is not well suited for running most modern appliances. The oscillator as mentioned earlier determines the output wave form. Therefore we would lay emphases on the square wave oscillator. The most common type of square wave inverters is based on astable multi-vibrator.
Limitations of square wave inverters
Despite the square wave being highly economical due its cheapness in terms of cost of production it has limitations such as:
High audio noise which turns to be very visible when it is being used to operate an audio system.
Incompatibility with certain communication gadgets such as fax machine, modems, routers and other equipment which run on motors such as fun, printers, photo copiers etc.
Low surge power
It is to this fact that new system like the modified sine wave which is built on the foundations of modified square wave is being introduced.

2.3.1.3 MODIFIED SQUARE/SINE WAVE INVERTER

An inverter allows the use of 230V electrical appliances from a battery or a solar battery. It must therefore supply a voltage that corresponds to an rms of 230 Volts sine-wave like household main supply or similar. Sine-wave voltages are not easy to generate. The advantage of sine-wave voltages is the soft temporal rise of voltage and the absence of harmonic oscillations, which cause unwanted counter forces on engines, interferences on radio equipment and surge currents on condensers. On the other hand, square wave voltages can be generated very simply by switches, which operated like a door bell were used for this task. They were called chopper cartridge and mastered frequencies up to 200 cycles per second. The efficiency of a modified square wave inverter is higher than the appropriate sine wave inverter, due to its simplicity. With the help of a transformer the generated modified square wave voltage can be transformed to a value of 230 Volts or even higher (radio transmitters).

Fig.2.3 Sine-wave voltage square wave voltage with both 230 Volt r.m.s

Fig.2.3 above shows a sine-wave as well as a square wave voltage with in each case an rms of 230 Volts. In both cases an electric lamp would light with the same intensity. This is, as we know, the definition of rms. As we recognize in figure 2.1 however the peak value of the sine-wave voltage is 325 Volts, i.e. factor √2 more than rms. For electrical lamps this is insignificant and electric engines are appropriate for it. Electronic devices were even designed for the peak voltage of sine-wave voltage, because internally they generate DC voltage from the AC supply voltage. A condenser will be loaded on exactly the peak value of the sine-waves. The industry nevertheless manufactured square wave inverters according to this principle in former times.
Our inverter works with a trick, to obtain the same results from square wave voltage as for modified sine-wave voltage.

Fig 2.4 Voltage with duty cycle 25% for 230 Volts rms.

Square wave voltage in figure develops the same peak value as sine-wave voltage of 230 Volts, i.e. 230 Volt * √2 = 325 Volts and nevertheless thereby obtains the demanded r.m.s of 230 V. Square wave voltage as shown in the previous figure (full half wave) with peak value of the corresponding sine-wave voltage would cause double amount of electrical power on electric consumers. The trick is, to switch the output power only for one half of every conducting cycle, thus resulting on a duty circle of 25% on behalf of the complete oscillation period. If the calculated double amount of electric power will be generated only half the time effective power remains the same. Industry called this cam shape modified sine, in order to be able to differentiate the devices from conventional square wave inverters.
The inverter may feed nearly all electrical appliances, designed for 230 Volts, with exception of rotary field engines that use condensers for generation of an auxiliary phase (condenser engines).
Engines of this type are used in most refrigerators, washing machines, dishwashers and some few machine tools. Fluorescent lamps with a series inductivity to limit the operating current wont work correctly on our inverter not necessary problem with the output waveform but in terms of power rating and specific function the inverter is designed for. The problem can be solved by increasing the duty cycle on more than 25% while decreasing the peak voltage to 275 Volts. Instead fluorescent lamps with electronics (energy saving lamps) will work very well on the inverter.
2.3.1.4 Modifying Sine Wave Using Discrete Square Waves

            Fig. 2.5 Modified Sine Wave

Referring to the figure alongside we can see an interesting design of a single modified sine wave cycle made by chopping a few square wave. Here, each positive and negative half cycle contain 3 discrete individual narrow square waves, each block is separated by a notch, the center two pillars are identical but are twice in magnitudes than the extreme ones.
The average value of this special arrangement of discrete square waves effectively imitates a sinusoidal wave. This configuration is as good as a pure sine AC waveform and thus will be suitable to operate almost all appliances safely.
In fact the present design is much more efficient than the usual circuits used in many inverters. From this circuit its possible to get an efficiency of almost 90%, because here the output devices are either turned fully on or fully off.

CHAPTER THREE

3.0 RESEARCH METHODOLOGY
3.1 BRIEF OUTLINE OF THE CHAPTER
This chapter reveals the research design and the different stages of the project are simply revealed. This chapter also reveals the concepts well as techniques adopted in the research about the project. The chapter also explains the various stages in an inverter design.
3.2 RESEARCH DESIGN
A comprehensive comparison of the strengths and weakness existing standard power inverters on the market were made and better system option in terms of the waveform its outputs and the compatibility with various electronic and electrical appliances. The design was centered on the availability and of electrical and electronic components on our local market not disregarding quality.
For smooth construction of this project the system was divided into three sectors namely, AC to DC converter for the charging of the battery, DC to AC inverter for the converting of battery power to (DC) to electricity (AC), and switching system for the co-ordination and synchronization of the system.

3.3 BLOCK BY BLOCK DIAGRAM OF AN INVERTER

Figs 3.1 Block Diagram of an inverter

The block diagram in the figure above illustrates the principle operation. The power supply fed to the battery for charging section, where it is being regulated for battery changing. Also to the power supply A.C mains sensor which senses the availability of power supply from the Electricity Distribution Company (EDC) of which is fed to the relay or change over section. If EDC power supply is present a signal; goes to the oscillator to block oscillation process, that is, oscillation should not take place and from the relay or change over section power is fed to the output socket for appliances usage. But if EDC is not available, a signal is also sent to start the oscillation process immediately, of which a 50Hz frequency is generated and it is the driver section and output amplifier suited the requirement of the output voltage the inverted transformer takes 12V power supply from the battery and also the amplifier signal from the output amplifier is fed into the inverted transformer and then it is fed into the relay or change over section in which it is further fed to the output socket for appliances usage.

3.3.1 Power Supply
This unit is mainly used to power the whole electronics component in the circuit and it must be a regulated power supply
3.3.2 Battery Charging Section
A battery charge is used to put energy into a cell or battery by forcing an electric current through it. The charging current depends upon technology methods and capacity of the battery being charged. A simple charger work by connection constant D.C power to the battery this is known as the floating charging which is adopted for this project.
3.3.3 The Relay or Change over Section
A relay is an electronic switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. Normally close contact disconnects the circuit when the relay is activated, the circuit is connected when the relay is inactive and it is called a break contact.
3.3.4 A.C Main Sensor Section
A.C main section which senses the availability of the power supply from which it is fed to the relay.
3.3.5 The Inverter System
The inverter system comprises of four stages; the oscillator stage, amplifier stage, power amplifier stage, power amplifier or driver stage and the transformer stage.
The Oscillator Stage
The oscillator stage is the heart of the device. The inverter needs to generate A.C voltage at a frequency of 50H, hence there has to be some kind of oscillator circuit for this to be achieved. The oscillator stage here is a pulse width modulator IC. The pulse width modulator has an internal RC oscillator, which could be made to oscillate the frequencies in excess of 1MHz, depending on the external component used. The advantage of using pulse width modulator is that the inverter gives low harmonic content of the frequency which is suitable for inductive loads.
The Amplifier Stage
The amplifier stage consist of an electronic amplifier that prepares a small electrical signal for further amplification or processing. Pre-amplifier further amplifies the signal generated from the oscillator before sending it to the driver stage.
Power Amplifier or Driver Stage
The input of the MOSFET has a very high impedance which makes the drive stage dispensable but when MOSFET are connected in parallel, it is often required that their gates be isolated. The driver stage not only matches the oscillator to the amplifier, but it also ensure that the gates of the parallel MOSFETs are properly isolated from each other even if they are driven from the same source.
Transformer Stage
The inverter transformer has two secondary windings. The switching action sends alternating current through the inverter transformer primary winding. This is referred to as push pull action. The core has bipolar utilization. The transformer turns ration can permit higher or lower load voltage. The inverter transformer output is and A.C square wave. Output filter network can be used to obtain sine wave

Find the voltage V1 and V2 using kvl

To Find V1 and V2, we’ll have to use ohm’s law and Kirchoff voltage law. Assume that current (I) flows through the loop

from ohm’s law, v = IR

so therefore, V1 = 4I,. V2 = -2I

Applying kvl around the loop given

-10 + V1 -8 – V2 = 0

-10 + (4i) -8 – (-2i) = 0

-10 + 4i -8 + 2i = 0

-18 + 6i = 0

6i = 18

i = 18/6; = 3A

so therefore, V1 = 4i; V2 = -2i

V1 = 4(3); 4×3. V2 = -2(3)

= 12V. =-6V

CIRCUIT THEOREM

1. With a suitable diagram show the alternating current and voltage in a pure resistance are to phase. Hence, derive an expression for power in a pure a.c resistive circuit.

R = resistance
From ohm’s law,
V = IR
VmSinwt = IR
I =(VmsinWt) ÷ R
Recall SinWt = 1
Current(I) is maximum(IM)
IM = Vm/R
Therefore,
Instantaneous current (I) = IMSinWt
Power across the circuit, V = VMSinWt
P = IV
P = IMSinWt × VMSinWt
P = VMIMSin2Wt
P =VmIM (1-cos2Wt)/2

2. A 60hz voltage of 180V (r.m.s) is impressed on 150Ω resistance. Write the time equation for the voltage across the resulting current.

F = 60hz, Vr.m.s = 180v, R = 150Ω
W = 2Πf = 2×3.142×60 = 377rads/sec.
VMAX = root 2 × Vr.m.s = root 2 × 180 = 254.56v
Vt = VmSinwt
Vt = 254.56Sin377t
Time equation for the voltage (Vt ) = 254.56Sin377t
I(t) = It Sinwt
But, maximum current (IM) = VM/R = 254.56/150 = 1.7A\
I(t) = 1.7Sin377t
Time equation for the resulting current (It) = 1.7Sin377t Ampere

ELASTIC PROPERTIES OF SOLIDS

Young Modulus
Young Modulus, y is defined as the ratio of tensile stress to tensile strain.
Y = tensile stress/tensile strain
Tensile strain is the ratio of the extension of a material to the cross sectional area of the material.
Strain = change in extension/ original length = e/L
Tensile strain has no unit
Tensile stress is the ratio of the force acting on a material to the cross sectional area of the material
Stress= force/area
Therefore, Y = tensile stress/tensile strain
= Force/area ÷ extension/original length
F/A × L/e = FL/Are
The S.I unit for y is N/m²
WORK DONE IN SPRINGS AND ELASTIC STRINGS
If an applied force, F caused an elastic spring of original length, l, to undergo an extension or comprehension, e, then the average force is;
= (0+F)/2 = ½F
Work done = force × distance
= ½F × e
W = ½Fe or ½Ke²
This is the work done by a spring when compressed or extended by a force. The energy stored in a spring or string is also given by W = ½Fe or ½Ke². The unit of work or energy is joules, j.

1. A spiral spring balance is 25.0cm long when 5N hangs on it and 30.0cm when the weight is 10N. What is the length of the spring if the weight is 2N, assuming Hooke’s law is obeyed?

Solution
Let the original length of the spiral spring be L
Extension, e = New length resulting from applied force – original length
First case: extension, e = 25-L
Applied force, F = 5N
2nd case: extension, e = 30-L
Applied force, F = 10N
Substitute into F = ke for 1st and 2nd cases.
1st. 5 = (25-L)k……………..(1)
2nd. 10 = (30-L)k…………..(2)
Make the subject of the formula,
K = 5/(25-L)………..(3)
K = 10/(30-L)………..(4)
Equate (3) and (4)
5/(25-L) = 10/(30-L)
Cross multiply both sides together
150-5L = 250-10L
Collect like terms
5L = 100
L = 20cm
Extension, e = 25.0 – L
25.0 – 20 = 5.0cm
= 0.05m( convert to meter)
Recall that, F = ke ( applied force is 5N)
K = f/e; = 5/0.05
K = 100N/m
What is the length of the spring if the weight is 2N,
e = F/k;
2/100 = 0.02m
= 2cm
New length of spring = Original length (L) + Extension (e)
20.0 + 2 = 22.0cm

2. A catapult used to hold a stone of mass 500g is extended by 20cm with an applied force F. Of the stone leaves with a velocity of 40ms–¹, the value of F is
   A. 4.0×10⁴N. B. 4.0×10³N. C. 2.0×10³N. D. 4.0×10²N
   Solution
   Mass = 500g = 0.5Kg( convert to kilogram) , e = 20cm = 0.2m, velocity= 40ms–¹
   F = ke
   Work done = ½mv²
   ½×0.5×40² = ½×0.5×1600
   W.D = 400j
   Recall that, W.D = ½Fe
   400 = ½×F×0.2
   F = 400/0.1
   F = 4,000N or 4×10³N
3. On top of a spiral spring of force constant 500Nm–¹ is placed a mass of 5×10–³Kg. If the spring is compressed downwards by a length of 0.02m and then released, calculate the height to which the mass is projected. (g=10ms–²)
   A. 8m B. 4m C. 2m D. 1m
   Solution
   Force constant, k= 500Nm–¹,. Mass = 5×10–³kg, length = 0.02m, height = ?
   The work done in compressing the spring is equal to the potential energy stored in the spring.
   ½ke² = mgh
   ½×500×(0.02)² = 0.005×10×h
   0.1 = 0.05h
   H = 0.1/0.05
   = 2m
4. A load of 5N gives an extension of 0.56cm in a wire which obeys Hooke’s law. What is the extension caused by a load of 20N?
   1.12cm B. 2.41cm C. 2.24cm D. 2.52cm
   Solution
   Force = 5N, e = 0.56cm( no need for conversion, since its unit of answer are in cm),
   First let’s find the constant value
   K = F/e = 5/0.56 = 8.93N/cm
   e = F/K = 20/8.93 = 2.24cm
5. Use the following data to determine the length, L of a wire when a force of 30N is applied, assuming Hooke’s law is obeyed.

SOLUTION
Force applied = 5-0 = 5N
Extension Length of wire (mm) = 500.5-500.0= 0.5mm
Constant, K = F/e = 5/0.5 = 10M/m
extension = F/k = 30/10 = 3mm
L = original length + Extension
500.0+3 = 503.0mm

EXERCISE TWO(2)

1. If a force of 50N stretches a wire from 20m to 20.01m, what is the amount of force required to stretch the same material from 20m to 20.05m
   A. 100N. B. 50N. C. 250N. D. 200N
   Solution
   Force = 50N, extension 1 = 20.01-20 = 0.01m,
   Find the constant k
   K = F/e
   50/0.01 = 5000N/m
   what is the amount of force required to stretch the same material from 20m to 20.05m
   Extension 2 = 20.05-20.0 = 0.05m
   F = Ke
   5000×0.05 = 250N. (C)
2. The extension in a spring when 5g weight was hung from it was 0.56cm. If Hooke’s law is obeyed, what is the extension caused by a load of 20g weight?
   A. 1.12cm B. 2.24cm. C. 2.52cm. D. 2.80cm
   Solution
   You shouldn’t be baffled about this just convert mass to newton (Force)
   Mass = 5g = 0.005kg, extension = 0.56cm
   Convert mass to newton
   Force= 0.005×10; = 0.05N
   Find constant, k = F/e
   0.05/0.56 = 0.089N/m
   what is the extension caused by a load of 20g weight?
   20g = 0.02×10
   0.2N
   extension,e = F/k
   0.2/0.089 = 2.24cm
3. A 10g mass placed on the plan of a spring balance cause an extension of 5cm. If a 15g mass is placed on the plan of the same spring balance the extension is?
   A. 3.3cm B. 6.5cm. C. 7.5cm. D. 10.8cm. E. 15.0cm
   Solution
   Do the same thing here, covert gram to newton
   Mass = 10g = 0.01kg
   Force = 0.01×10 = 0.1N
   extension 1,e = 5cm
   Find constant k,
   K = F/e
   0.1/5 = 0.02N/m If a 15g mass is placed on the plan of the same spring balance the extension is?
   Force, F = 0.015×10 = 0.15N
   Extension, e = F/k
   0.15/0.02 = 7.5cm
4. The total length of a spring when a mass of 20g is hung from its end is 14cm, while its total length is 16cm when a mass of 30g is hung from the same end. Calculate the unstretched length of the spring assuming Hooke’s law is obeyed.
   A. 9.33cm. B. 10.00cm. C. 10.66cm. D. 12.00cm. E. 15.00cm
   Solution
   Mass = 20g, force = 0.2N, extension = 14cm
   Mass= 30g, force = 0.3N, extension = 16cm
   F = Ke
   0.2 =k(14-L)……………………………….(1)
   0.3 = k(16-L)……………………………….(2)
   Make k the subject of the formula
   K = 0.2/(14-L)……………………………..(3)
   K = 0.3(16-L)………………………………(4)
   Equate (3) and (4)
   0.2/(14-L) = 0.3(16-L)
   3.2-0.2L = 4.2-0.3L
   0.3L-0.2L = 4.2-3.2
   0.1L = 1.0
   L = 1.0/0.1 = 10.00cm
5. A force of 100N stretches an elastic string to a total length of 20cm. If an additional force of 100N stretches the string 5cm further, find the natural length of the spring.
   A. 15cm. B. 12cm. C. 8cm. D. 5cm
   Solution
   F = 100N, original length = 20cm, extension = 5cm
   Length = original length- extension
   20-5 = 15cm
6. The spiral spring of a spring balance is 25.0cm long when 5N hangs on it and 30.0cm long when the weight is 10N. What is the length of the spring if the weight is 3N assuming Hooke’s law is obeyed?
   A. 15.0cm. B. 17.0cm. C. 20.0cm. D. 23.0cm
   Solution

Force = 5N, extension = 20.0cm
Force = 10N, extension = 30.0cm
F = Ke
5 =k(20-L)……………………………….(1)
10 = k(30-L)……………………………….(2)
Make k the subject of the formula
K = 5/(25-L)……………………………..(3)
K = 10(30-L)………………………………(4)
Equate (3) and (4)
5/(25-L) = 10(30-L)
150-5L = 250-10L
10L-5L = 250-150
5L = 100
L = 100/5 = 20.00cm
Considering the first case;
Extension, e = 25.0-L = 25-20
5cm = 0.05m
Applied Force = 5N
From, f = Ke, force constant, k = F/e = 5/0.05
= 100N/m
for F = 3N and K = 100N/m
Extension,e = F/k
3/100 = 0.03m = 3cm
Therefore, New length of spring = Original length (L) + Extension (e)
20cm+3cm = 23cm

7. A force of 15N stretches a spring to a total length of 30cm. An additional force of 10N stretches the spring 5cm further. Find the natural length of the spring.
   A. 25.0cm. B. 22.5cm. C. 15.0cm. D. 20.0cm
   Solution
   Force = 15N, extension = 30.0cm
   Force = 10N, extension = 5.0cm
   Find the natural length of the spring,
   Assuming, the both force are 10N then the natural length will be 30-5 = 25cm
   So because of the 15N, it should be 22.5cm
8. A piece of rubber 10cm long stretches 6mm when a load of 100N is hung from it. What is the strain?
   A. 60. B. 6. C. 6×10–³. D. 6×10–³
   Solution
   Length, L = 10cm = 100mm
   Extension, e = 6mm
   Strain = extension/length
   6/100 = 0.06 = 6×10–²
9. A load of 20N on a wire of cross-sectional area 8×10–⁷m², produces an extension of 10–⁴m. Calculate Young’s Modulus for the material of the wire if it’s length is 3m.
   A. 7.0 × 10¹¹Nm–². B. 7.5 × 10¹¹Nm–². C. 8.5 × 10¹¹Nm–². D. 9.0 × 10¹¹Nm–²
   Solution
   Force F = 20N, length = 3m
   Area = 8×10–⁷m², extension = 10–⁴m.
   Young Modulus = FL/Ae
   (20×3) ÷ (8×10–⁷ × 10–⁴)
   60/8×10–¹¹ = 7.5 × 10¹¹Nm–².
10. The tendon in a man’s leg is 0.01m long. If a force of 5N stretches the tendon by 2.0 × 10–⁵m, calculate the strain on the muscle.
    A. 5 × 10⁶. B. 5 × 10². C. 2 × 10–³. D. 2 × 10–⁷
    Solution
    Strain = extension/length
    0.00002/0.01 = 2 × 20–³
11. If the stress on a wire is 10⁷Nm–² and the wire is stretched from its original length of 10.0cm to 10.05cm. The Young modulus of the wire is
    A. 5.0×10⁴Nm–². B. 5.0×10⁵Nm–². C. 2.0×10⁸Nm–². D. 2.0×10⁹Nm–²
    Solution
    Young modulus = stress/strain
    Stress = 10⁷Nm–²
    Length = 10.0cm
    Extension e = 10.05-10.0 = 0.05cm = ,0.0005m
    Strain = extension/length
    0.0005/0.1 = 0.005
    Young modulus = 10⁷/0.005
    = 2.0×10⁹Nm–²
12. A spring of force constant 1500Nm–¹ is acted upon by a constant force of 75N. Calculate the potential energy stored in the spring.
    A. 1.9j. B. 3.2j. C. 3.8j. D. 5.0j
    Solution
    Constant, k = 1500Nm–¹. Force F = 75N
    Potential energy = ½Fe
    Find extension
    F = Ke
    e = F/K
    75/1500 = 0.05m
    Potential energy = ½Fe
    ½×75×0.05 = 1.875J
    Approximately = 1.9J
13. A spring of length 25cm is extended to 30cm by a load of 150N attached to one of its ends. What is the energy stored in the spring?
    A. 3750J. B. 2500J. C. 3.75J. D. 2.50J
    Solution
    What is the energy stored in the spring?
    Extension = 30-25 = 5cm = 0.05
    Energy stored = ½Fe
    ½×150×0.05 = 3.75J
14. The energy contained in a wire when it is extended by 0.02m by a force of 500N is
    A. 5J. B. 10J. C. 10³J D. 10⁴J
    Solution
    What is the energy stored in the spring?
    Extension = 0.02m
    Energy stored = ½Fe
    ½×500×0.02= 5J
15. 50.0kg block is dropped on a spring from a point 10m above ( above figures). If the force constant of the spring is 4.0×10⁴Nm–¹, find the maximum compression of the spring [g = 10m/s²].
    A. 1.25m. B. 0.50m. C. 0.25m. D. 0.05m
    Solution
    Mass = 50.0kg,. Length = 10m, force constant k = 4.0×10⁴Nm–¹, gravity = 10ms–²
    ½Ke² = mgh
    ½×40000×e² = 50×10×10
    e² = 5000/20000
    e = √0.25
    e = 0.50m

FABRICATION AND INSTALLATION OF WORKSHOP METAL DOOR

IN PARTIAL FULFILMENT OF THE REQUIRMENT FOR THE AWARD OF NATIONAL DIPLOMA IN MECHANICAL ENGINEERING TODEPARTMENT OF MECHANICAL ENGINEERING,FACULTY OF ENGINEERING, THE POLYTECHNIC, IBADAN.
JULY, 2021

This is to certify that this project titled “Fabrication And Installation of Metal Door” was carried out by following under listed students.
ADEROGBA ABDULAHMED ADENIYI 2018232060016
ADETAYO OLAMILEKAN DAVID 2018232060017
AFOLABI VICTOR AYOMIDE 2018232060019
AHMED JUBRIL OLAMILEKAN 2018232060021

In partial fulfillment of the requirement for the award of National Diploma certificate in the Department of Mechanical Engineering , Faculty of Engineering of The polytechnic, Ibadan, Oyo State.
____ _
ENGR. ADIO, T.A DATE

___ __
ENGR. OKE, D.B DATE

DEDICATION

This project is dedicated to Almighty God, the creator of all the creatures, whose mercy embraces all things, and strength dominates whatever exists in any form. It is also dedicated to our parents.

ACKNOWLEDGEMENT

Firstly, we give thank to God Almighty the author and the finisher of our faith for his protection over us through out the course of our life and our stay in this institution. We acknowledge the immense contribution of our parents who ensured our stay in the institution was fruitful and our fellow colleagues and supervisor in the department who has been helping through out the construction of the project, we say thank you all, we express our sincere gratitude to you all.
Also, special thanks goes to our project supervisor in person of Egnr, Adio, T.A and Mr. Oyedeji O., Who had been magnanimous enough in correction and suggestion which enable the success of this project. Thanks for been such a wonderful and understanding supervisor God bless you sir. Favor and blessing are the house hold of our mighty God, may that favors and blessing never depart from each one of us Amen.

ABSTRACT

This project is based on fabrication of metal door. A metal door is a movable structure used to close off an entrance typically consisting of a panel that swings, slide or rotate.
This metal door more reliable and strong and has much good working appearance than other doors like, wooden door, glass door, leather door and so on. Various fabrication processes such as marking out, cutting, bending, joining or welding, grinding, spraying and so on were adopted and implemented in the fabrication of this twin leaf metal door, peep hole was fixed on the door to screw visitor and admit on choice, the main purpose is to ensure safety and protection.
The material used to make this project to be a well strong design are as follows: galvanized metal plate, square pipe, lockset key, paint, hinges guage, 2electrode and grinding disk and the major reason of using the material is to provide good making features of the door which will meet up with now adays demand and designs, and in order to expose students on how to use different types of simple tools and some machines. The special features on the door are as follows, pinhole, lockset key, hinges small, square pipes, paint which is use to coat the door against rusting.

CHAPTER ONE

INTRODUCTION
The existence of metal door can be traced back to the olden days when our fore fathers constructed the cross planks on their windows. The aim of these is to prevent any kind of intruders into their houses. Due to the advancement in the nature of nowadays, the cross planks is unfit for such a task any more(Water,2002) .
Due to some societal problems such as metal door act ,man now devices a better way of protecting their lives and property by using an iron made materials, for their door.
In this project, we are dealing with the usage of the sheet metal for metal door.
Types of door
Wooden door: This is type of door made from wood of different types carried to beautify houses and offices.
Metal door: This is a type of door made from steel which compromised either of polyurethane or polystryrenecore, hollow pipe is placed over the top of the constructed door.
Aluminum door: This is the type of door made from aluminum metal and it is commonly use in many residential and official buildings. This is due to the light density, corrosion resistance, aesthetic, with optional fix wood texturing and long lasting finished. Aluminum is the lighter and less expensive than steel but more prone to dent.
Fiber glass door. Fiber glass door represent a small segment of the market. This panels, which are encased in aluminum frames can be painted to overcome great resistance to salt water corrosion the other garage door materials which make a good choice for coaster location.

Research Problem.

In the past decade, the upsurge income rate has been a recurring problem in the country adjust as measure needs to be installed. The introduction of metal door in place of wooden door for automobile workshop in order to improve security measures and forceful entry.
Wooden doors unlike metal doors are prone to spoilage easily when being exposed to excess sunlight, rainfall, insects(termites) can actually feeds on it and causes it to get damaged.

Aim and Objective

Aim
The project has been fabricated and installed at the automobile workshop.
Specification Objective
The specification objectives of this project is to
To select appropriate materials for the construction of meetal door
To fabricate metal door on (i) to department specifications (ii) compliance with all required specification, standards and proper construction procedures
Scope and Limitation
Scope
The scope is based on the various construction operation carried out in the production of metal door such as marking out, cutting, bending and assembling. The material used is based on the cost and environmental influence of the automobile workshop
Limitations.
There is rusting n metal frames and metal sheet
It is impossible to present in architectural vies.
Expected Contribution To Knowledge.
Serves as source of encouragement to man power development.
It also improve the protection of lives and properties.
It encourage the use of locally fabricated (metals) door in the society.

CHAPTER TWO

LITERATURE REVIEW
Doors date back from ancient Egyptian era, there are painting which serves as historical records of door architecture. The climate in Egypt was hot and dry enough, that there was not any fear of war print that the wood used for doors were just that, slaps of wood or hinges.
Doors were invented as a means of providing security for lives and property through locking up. The oldest door in England can be found in the west minister Abbey. The earliest Renaissance door in France are those of the cathedral of (St. Sauveur at Six (1503) returning to Italy).
In most places due to change of temperature and humidity. Doors usually have to be framed. Others historical records of doors include king Solomon’s temple doors. They were made of olive wood, as many doors of the past. In India, there were ancient stone door found. These had pivots on each end, which then fit into sockets. These doors swung open and sheet, similar to saloon door of old west but not as quickly. The greek and Romans used many styles of doors; single, double and folding. These doors are as well as many others found through out Europe’s past were made of bronze. This seemed to be going of today market can be made from any material just found on earth, wood, plastic, metal, glass, Paper and even fabric. They usually serve the purpose of keeping something in and or out.
Franklin o. Joues (2007) defines metals solid materials that are typically hand, shinning, malleable feasible, and ductile with a good electrical and thermal conductivity some metal, forms barrier layer of oxide on their surfaces which cannot be penetrated by further oxygen molecules and they retain their shining appearance and food conductivity for many decades e.g aluminum, magnesium, and steel which are titans.
Ran rah shah(2002) defined metal as a substance that has a bright lust and is good conduction of electricity. Metal having varying degree of hardness, density/malleability and ductility ( being malleable) to be will out and hammered.
Porter Catherine(2011) also said that a metal has a definite melting points and will fuse with other metals to form alloys with the exception of mercury. All metals are found in pure state but most of them are found in combination ores are lead, zinc, iron, copper, chromium, nickel and Mercury.
Ancient and Medieval periods: Few doors have been preserved from the period of antiquity. Those of some important building were bronze but seem unlikely that most does could have jambs and support an entablature. Finally a full or broken pediment or triangular or segmental or scroll form may crown the entablature. Pediment discharge reinforce to the slide of the doctor instead of allowing it to drip down in form of door ways for this type appears in the Renaissance during the fifteenth century in Italy and continued in latter styles through the early twentieth century. A fairly elaborate example is the door ii ovens in Rome Criacomo Della portal is where triangular pediment are set within a large segmental pediment (Giacomo1995).
According to Chapman (1970) theory of bending the cost and simplicity of which tools are designed and made will depend on the scale of the output envisages. For example a firm out to procure common articles such as safety pin or picture hood expect the market to absorb large quantities and should provide tools with high output and long life.

2.1 DOORS

One of the weak sports through thieves often try to make their way into a home is door. Only doors fashioned from study materials, fitted with a security lock and inside a solid frame with a quality lock, retainer and window still are burglary proof.(Philip Willekens,2007).
Door and frame should always form whole. This is the only way to tend burglars powerless!
2.1.1 Definition of a Door
A door is a hinged or otherwise movable barrier that allows ingress into egress from an enclosure. The created opening in the wall is a door way or partial. Door are commonly attached by hinges, but can move by other means such as slides or counter balancing.
2.1.2.Forcefield
Force field is an area of energy, such as magnetic energy, surrounds an object or place. A force field analysis is a development in social science. It provide a frame work for looking at the factors that influence in a situation, originally social situation it looks at forces that are either driving movement toward a goal or blocking movement toward a goal.
2.1.3.Contactforce
A contact force is any force that acquires contact to occur. Contact forces are ubiquitous and are responsible for most visible interaction between macroscopic collections of matter.
2.2 Types of Door
I. Wooden door
ii. Fiber glass door
III. Steel door
iv. Aluminum door
Wooden door
Wooden doors or timber doors are primarily used for interior door applications. Timber is the oldest material used for the doors and timber never seems out of fashion. There are many good reasons for using wood such as wooden doors provide sound proofing. Insulation and security. They are easy to install and clean. They have long life. Being natural material, they have a different appeal. They do look elegant. They are very costly.

Fig 1.1 A wooden door
Fiber glass door
Fiber glass garage doors represent a small segment of the market. The panels, which are encased in aluminum frames, can be painted and offer, greater resistance to dents than steel.
Fiber glass is very light, a poor insulator, and can fade from weather exposure. But it is more resistance to salt water corrosion than other garbage door materials, which makes it a good choice for coastal location.

Fig 1.2 Finer glass door
Steel doors
Steel doors are compromised of either a polyurethane or polystyrene core with a steel skin over the top. A solid steel door would be prohibitively heavy and would mostly likely tear out the hinges. Steel between 16 and 24 gauge is used for the skin of the door.
Steel doors have additional pvc vinyl layer adhered to the steel skin which gives the door a certain look or color,. typically wood gain, it should be noted that these pvs vinyl layers are hard to paint if you later decide that you want different colour. They are 500% better at blocking unwanted heat and cold than are wood doors.

Fig 1.3 Steel door
Aluminum doors
Aluminum doors share many of the characteristics of steel, with optional fax wood texturing and long lasting finishes. Aluminum of lighter and less expensive that steel, but it is more likely to dents.

Fig 2.4 Aluminum door
2.3.1 Advantages of metal door
Metal door provides the following benefits
This door is effortless to handle.
It can only be placed on a door frame with durability and easy installation.
Using paints, we can keep it for a long time.
As the price is not high, all classes of people can afford it.
The metal doors comes in various form.
Fire rated metal door is a great way to include extra light in a room, providing additional security.
2.2.3 Disadvantage of metal doors
The disadvantage of metal door are:
It has a rusting problem.
It cannot give an architectural view.
This might be heavy in weight.
2.4 Definition of Welding
Welding is a fabrication or sculpture process that joins materials, usually metals or thermoplastics by causing coalescence. This is often done by melting the work pieces and adding a filter material to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower melting point material between the work pieces to form a bond between them without melting the work pieces.(Lincoln Electric,1994).

2.5 Types of Welding

1. Arc welding: These processes use a welding power supply to create and maintain an electric are between an electrode and the base material to melt metals at the welding point. They can use either direct current (DC) or alternating current (AC), and consumable or non-consumable electrodes.
2. Gas welding: The most common gas welding process is oxy-fuel welding, also known as oxyacetylene welding. It is one of the oldest and most versatile welding processes, but in recent years, it has become less popular in industrial applications. It is widely used for welding pipes and tubes, as well as repair work.
3. Resistance welding: These involves the generation of heat by passing current through the resistance caused by the contact between two or more metal surface. In general, resistance welding methods are efficient and cause little pollution, but their applications are somewhat limited and the equipment cost could be high.
4. Solid-state welding: This is the joining of base metals (Metals, alloys, ceramics etc.) by chemical bond formation without heating the base metals above their respective melting point.

A 60Hz voltage of 280v effective value is impressed on an inductance of 0.356H.

• Write the time equation for the voltage and the resulting current.
• Find the maximum energy stored in the inductance.

Solution
F = 60Hz, V = 280v, L= 0.356H

Time equation for the resulting voltage
V = VoSin2πft
The root mean square voltage, V
V = `Vo/2
Vo = V × 2
280 × 1.4142 = 395.98V

RESULTING VOLTAGE,
V = VoSin2πft
V = 395.8Sin2 ×3.142 × 60 ×t
V = 395.8Sin377t
Io = Vo/XL

LOAD REACTANCE, XL = 2πfL
XL = 2 ×3.142 ×60 ×0.356
XL = 134.25Ω
Io = 395.8/134.23
Io = 2.95A

TIME EQUATION FOR CURRENT,
I = Io sin [wt – π/2]= 2.95sin[377t – π/2]

Find the maximum energy stored in the inductance.
E = ½ LIRAISE TO POWER 2 max
= ½ ×0.356 ×2.95 ×2.95
= 1.55J

An Electrical amplifier when first built has an open loop gain of 120 after a while due to ageing
this falls to 90. Calculate the percentage reduction in gain.
Av (original) = 120, Av (aged) = 90
% reduction = Original gain – New gain x 100%
Original gain
= 120 – 90 x 100
120
= 25%
So the gain has fallen by 25% – not good:
If the same amplifier has 10% of negative feedback applied, calculate the gain with
feedback before and after ageing. Determine the percentage reduction in gain and
comment on the improvement resulting from negative feedback
Application of negative feedback
 = 10% = 0.1
Anfb (original) = 120
1 + (120 x 0.1)
= 120
13
= 9.2
Anfb (aged) = 90
1 + (90 x 0.1)
= 9.0
% reduction = 9.2 – 9 x 100
= 2.17%
So without negative feedback ageing caused a reduction in gain of 25% but with
negative feedback applied the reduction in gain is only 2.17%.
2.2 VERY HIGH GAIN AMPLIFIERS
There are many instances where the open loop gain of an amplifier is very high, i.e.
100,000 in a case like this

(1) Answer True or False to the following questions

QUESTIONS

a. Both a spring balance and a chemical balance are used to measure the mass of an object.

Answer

False the spring balance is used to measure weight while the chemical balance is used to measure mass of an object.

b. Hooke’s law form the basis of operation of the spring balance

Answer

yes, because the more the spring balance stretch or extends determine the weight of an object. I.e the extension of a spring balance is proportional to the weight of the body.

C. The chemical balance works on the principle of moments.

Answer

True, because this involves two bodies and a lever.

d. A micrometer screw Guage can be used to measure the internal diameter of a tube.

Answer

False, because it’s used to measure the external diameter of an object and the internal diameter can be best done by a vernier caliper.

e. For a ruler graduated only in centimeters, measurement can be made accurately to the nearest millimeter.

Answer

False, because a measurement is limited to one-half of the smallest division on the ruler or 0.5cm (5 millimeter)

(2) Each of the quantities in the following list is indicated as a scalar or vector quantity. Answer True if the classification is correct and False of not.

QUESTIONS

a. Pressure [ vector]

b. Electrical potential [scalar]

c. Impulse [vector]

d. Heat capacity [scalar]

e. Altitude [ vector]

f. Electrical potential difference [vector]

g. Magnitude induction [scalar]

h. Acceleration due to gravity [vector]

i. Momentum [ vector]

j. Power [scalar]

k. Electrical field [scalar]

l. Electrical current [vector]

ANSWERS

a. Pressure [ vector] True✓

b. Electrical potential [scalar] True✓

c. Impulse [vector] True✓

d. Heat capacity [scalar] True✓

e. Altitude [ vector] False ×

f. Electrical potential difference [vector] False ×

g. Magnitude induction [scalar] false×

h. Acceleration due to gravity [vector] True✓

i. Momentum [ vector] True✓

j. Power [scalar] True✓

k. Electrical field [scalar] False×

l. Electrical current [vector] false ×

(3) In the following list the unit of each quantity is indicated in brackets. Answer True(T) if the indicated unit is correct and False (F) if not.

QUESTIONS

a. Work [kgm²s-²]

b. Power [ Js]

c. Gravitational potential [jkg-¹]

d. Pressure [kgm-¹s-²]

e. Specific latent heat [ jkg-¹k-¹]

f. Density [ kgm-³]

g. Elastic modulus [Nm-¹]

h. Electric field [Nc-¹]

I. Potential difference [Jc-¹]

j. Resistivity [Ωm-¹]

ANSWERS

a. Work kgm²s-²

Solution

Work = force × distance

= Mass × acceleration × distance

= Kg × ms-² × m

= Kgm²s-²

b. Power [ Js] [False]

Solution

Power = work done/ time taken

= (Force × distance)/time taken

= (Mass × acceleration × distance) time taken

= (Kg × ms-² × m)/s-¹ i.e j/s

= Kgm²s-³ or j/s

c. Gravitational potential [jkg-¹] True

d. Pressure [kgm-¹s-²] [ True]

Solution

Pressure = force/ area
= Mass × acceleration / area
= Kg × ms-² / m²
= Kg × ms-² × m-²
= Kgm-¹s-²
e. Specific latent heat [ jkg-¹k-¹]. (False)
solution
Specific latent heat is jkg-¹
f. Density [ kgm-³] True
g. Elastic modulus [Nm-¹] false
Solution
Nm-²
h. Electric field [Nc-¹]Answer
True (Nc-1)
I. Potential difference Jc-¹
Answer
Voltage, V is the same as jc-¹
j. Resistivity Ωm-¹
Answer
Ωm