It has op-amp as the amplifying stage and three RC cascaded RC network as the feedback circuit. The op-amp is used as an amplifier. The feedback circuit provides feedback voltage from the output back to the input of the amplifier. The op-amp is used in the inverting mode. Thus, op-amp gives a phase shift of 180° at the output. An additional 180° phase shift required for oscillations is provided by the 3 RC networks.
When the power supply is switched on, the noise voltage induced between the pin numbers 2 and 3 is amplified by the op-amp producing a phase shift of 180°. The output is fed to RC phase shift network which introduces a total phase shift of 180° by charging and discharging action of a capacitor through the resistors. Each RC network produces a phase shift 60° and hence three RC
\(f=\frac{1}{2\pi RC \sqrt{6}}=\frac{0.065}{RC}\)
The feedback fraction is \(\beta =\frac{R_i}{R_f}=\frac{1}{29}\)
