Question

Which of the following network is used to give feedback to transistor?

(a) Inductive fixed bias

(b) Capacitive fixed bias

(c) Inductive voltage divider

(d) Capacitive voltage divider

This question was posed to me in an interview for internship.

I'd like to ask this question from Colpitts Oscillator-1 in section Oscillators of Analog Circuits

Answer 1

Correct answer is (d) Capacitive voltage divider

The explanation is: Capacitive voltage divider network is used for giving positive feedback in Colpitts oscillator. Oscillations across the capacitor are applied at the base-emitter junction and appear across the collector as an amplified output. The amount of feedback depends on the ratio of the two capacitors being used.