Question

What would be the value of feedback voltage in a negative feedback amplifier with A=100; β =0.03 and input signal voltage = 40mv?

(a) 0.03V

(b) 0.06V

(c) 0.09V

(d) 0.12V

This question was addressed to me during an interview.

This question is from Properties of Negative Feedback topic in portion Differential and Multistage Amplifiers of Electronic Devices & Circuits

Answer 1

The correct option is (d) 0.12V

The best I can explain: Given: A =100;    β = 0.03

Vi = 40mV

To determine:    feedback voltage {Vf} for negative feedback amplifier;

Formula Used:    Vf =  β * Vo

Vf =  0.03*(100*40*10-3)

Vf =  0.12V

Therefore, the feedback voltage is 0.12V for given parameters of negative feedback amplifier.