Question

The maximum a.c. power output from a class A power amplifier is 10 W. What should be the minimum power rating of the transistor used?

(a) 20W

(b) 5 W

(c) 25W

(d) 50W

I had been asked this question in a job interview.

This interesting question is from Class A Output Stage in portion Differential and Multistage Amplifiers of Electronic Devices & Circuits

Answer 1

Correct answer is (a) 20W

Best explanation: Maximum AC power is given as;

P0 =  (VCEQ . ICEQ)/2

So the minimum power rating used should be,

10W * 2 = 20W.