Question

Consider the given diagram. Loop gain is 19. Consider closed loop gain is 50. Find the output without any feedback when input is 5.

(a) 1000

(b) 500

(c) 5000

(d) 50000

I had been asked this question in an interview for job.

This interesting question is from Effects of Feedback in division General and Feedback Amplifiers of Analog Circuits

Answer 1

Correct choice is (c) 5000

To elaborate: Feedback factor, β=10.

AF = A/(1+Aβ) = 50

A = 20*50 = 1000

Output is thus 5000.