Types of Oscillator
- Armstrong Oscillator
- Hartley Oscillator
- Colpitts oscillators
- Wine bridge oscillator
- Crystal oscillator
- RCPhase shift oscillator
- Dynatron oscillator
- Tuned collectors oscillator
- Clapp oscillator
- Voltage Controlled Oscillator
- Armstrong oscillator
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.
HARTLEY OSCILLATOR
The Hartley oscillator is an electronic oscillator. The frequency of this oscillation is determined by the tuned circuit. The tuned circuit consists of the capacitor and inductor, hence it is an LC oscillator. In 1915 by American engineer Ralph Hartley has invented this oscillator. The features of the Hartley circuit are the tuned circuit consists of a single capacitor in parallel with the two inductors which are in series. From the center connection of the two inductors for oscillation purpose, the feedback signal is taken.
COLPITTS OSCILLATOR
The Colpitts Oscillator was by American engineering by Edwin H. Colpitts in the year of 1918.This oscillator is a combination of both inductors and capacitor. The features of the Colpitts Oscillator are the feedback for the active devices and they are taken from the voltage divider and made up of two capacitors which are in series across the inductor. The Colpitts circuits consist of gain devices such as the bipolar junction, field effect transistor, operational amplifier and vacuum tubes.The output is connected to an input in a feedback loop it has a parallel tuned circuit and it functioned as a band-pass filter is used as a frequency of the oscillator. This oscillator is an electrically dual of the Hartley oscillator hence the feedback signal is taken from the inductive voltage divider, it has two coils in the series.
WIEN BRIDGE OSCILLATOR
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.
CRYSTAL OSCILLATOR
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.
RCPHASE-SHIFT OSCILLATOR
A phase-shift oscillator is a linear electronic oscillator circuit that produces a sine wave output.Itconsists of an inverting amplifier element such as a transistor or op-amp with its output fed back to its input through a phase-shift network consisting of resistors and capacitors in a ladder network. The feedback network ‘shifts’ the phase of the amplifier output by 180 degrees at the oscillation frequency to give positive feedback. Phase-shift oscillators are often used at audio frequency as audio oscillators.
The filter produces a phase shift that increases with frequency. It must have a maximum phase shift of more than 180 degrees at high frequencies so the phase shift at the desired oscillation frequency can be180 degrees.The most common phase-shift network cascades three identical resistor-capacitor stages that produce a phase shift of zero at low frequencies and 270° at high frequencies.
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.
TUNED COLLECTORS OSCILLATOR
Tuned collectors oscillator
Tuned circuit oscillators are the circuits that produce oscillations with the help of tuning circuits.The tuning circuits consists of an inductance L and a capacitor C. These are also known as LC oscillators, resonant circuit oscillators or tank curcuit oscillators.The tuned circuit oscillators are used to produce an output with frequencies ranging from 1 MHz to 500 MHz. Hence, these are also known as R.F. Oscillators. A BJT or a FET is used as an amplifier with tuned circuit oscillators. With an amplifier and an LC tank circuit, we can feedback a signal with right amplitude and phase to maintain oscillations.
CLAPP OSCILLATOR
The Clapp oscillator or Gouriet oscillator is an LC electronic oscillator that uses a particular Clapp oscillator of an inductor and three capacitors to set the oscillator’s frequency. LC oscillators use a transistor (or vacuum tube or other gain element) and a positive feedback network.The oscillator has good frequency stability.
VOLTAGE-CONTROLLED OSCILLATOR
Voltage-controlled oscillator
A voltage-controlled oscillator is an oscillator with an output signal whose output can be varied over a range, which is controlled by the input DC voltage. It is an oscillator whose output frequency is directly related to the voltage at its input. The oscillation frequency varies from few hertz to hundreds of GHz. By varying the input DC voltage, the output frequency of the signal produce disabused.
