Question

Circuit P has desensitivity 20, circuit Q has sensitivity 0.1 and circuit R has desensitivity 40. Which of the following is more stable in gain?

(a) Circuit P

(b) Circuit Q

(c) Circuit R

(d) All circuits are equally stable in gain

I had been asked this question in exam.

The above asked question is from Effects of Feedback in section General and Feedback Amplifiers of Analog Circuits

Answer 1

Correct option is (c) Circuit R

To explain: Greater desensitivity indicates better stability in gain. More desensitivity means gain becomes smaller, but stable.

For circuit Q, desensitivity = 1/S = 10

Circuit R has higher desensitivity, hence most stable.