Question

Which of the following is not a reason for beginning oscillations in RC phase shift oscillator?

(a) Phase shift network

(b) Noise inherent in transistor

(c) Minor variations in the voltage DC source

(d) Square wave signal

This question was addressed to me during an interview.

My query is from RC Phaseshift Oscillator topic in section Oscillators of Analog Circuits

Answer 1

Right option is (a) Phase shift network

For explanation: Phase shift network doesn’t initialize the oscillation it just phase shift a given frequency. Oscillation will start by noise inherent of transistor or by minor voltage variations in DC source.