[UPSC CSE 2007] Semiconductors/Solar cell (Q245, 25M)

Explain the working of a phase-shift oscillator. Draw the circuit diagram of a phase-shift oscillator using either a transistor or an op-amp. What are the conditions which must be satisfied to achieve stable oscillations ? Calculate the frequency of oscillations for R = 10\ \Omega and C = 0.01\ \mu\text{F}.