Explain working of Phase Shift Oscillator?

Figure shows a phase shift oscillator. Here the combination of ReCe provides self bias for the amplifier. The phase of the signal at the input(for the time being, we assume the presence of the signal at the input)gets reversed when it is amplified by the amplifier. The output of the amplifier goes to a feedback network. The feedback network consists of three identical Rc sections. Each RC section provides a phase shift of 180⁰ 1 thus a total of 60×3 =180⁰ phase shift is provided by the feedback network. The amplifier provides 180⁰ phase shift. Total phase shift is 360⁰

. the output of the feedback network is now in same phase as the originally assumed input to the amplifier. If the condition A? = 1 is satisfied, oscillations will be maintained. From this, the frequency of oscillation is given by

The range of frequency is from several hertz to several hundred hertz. It is used for producing audio frequency range. If we change any value of capacitor or any value of resistor we can change the frequency. The value of 3 capacitor change simultaneously then a large change is developed is frequency.