RC Phase Shift Oscillator Using Transistor (BJT): Circuit & Working

In this section we would like to introduce you a transistor oscillator circuit, called as RC Phase shift Oscillator. First of all we need to know what is an oscillator. An oscillator is an electronic circuit which acts as a sine wave generator. The only requirement of an oscillator is a DC power supply source. It is widely used in frequency variab

le signal generators, so it is a common basic electronic circuit. We had already discussed about Op amp RC phase shift oscillator in earlier posts. Different types of oscillators are available which are based on their performance and components used, like Wein bridge oscillator, Hartly Colpitts oscillator etc. Here we are going to study how we can obtain RC Phase shift Oscillator using a silicon transistor. In an oscillator the frequency generating circuit is decided by the circuit elements used. A basic oscillator circuit contains the following parts If we use a common emitter amplifier with a resistive collector load, there will be a 180 phase shift between the voltages at base and collector. It will also amplify the signal. Three sections of phase shift networks are used which is constituted by resistive-capacitor combination. In that each section introduces 60 phase shift at resonant frequency. Phase shift oscillator is a particular type of audio frequency oscillator. Output signal is obtained across 1 µF capacitor and ground terminal as shown in circuit schematic. If all the resistors, R and the capacitors, C in the phase shift network are equal in value, then the frequency of oscillations produced by the RC oscillator is given as: Number of RC stages will improve the frequency permanence. The total phase shift established by the feedback network must be 180 degrees for sustained oscillations. If we are using N` RC...

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