Question

The range of β is _________

(a) 20 to 500

(b) 50 to 300

(c) 30 to 400

(d) 10 to 20

This question was addressed to me at a job interview.

My query is from The Common Emitter Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits

Answer 1

Right option is (a) 20 to 500

For explanation I would say: Almost in all the transistors, the base current is less than 5% of the emitter current. Due to this fact, it is generally greater than 20. Usually it ranges from 20 to 500. Hence this configuration is frequently used when appreciable current gain as well as voltage gain is required.