Question

A Self bias configuration contains RD=3.3,  Rs=1 KΩ,  RG=1MΩ and gm=1.5mS. Determine Av?

(a) -2

(b) 3

(c) -4

(d) 5

This question was posed to me by my school principal while I was bunking the class.

My question is taken from The Common Source Amplifier topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer 1

Correct choice is (a) -2

The explanation: Av=-gm RD/ (1+gm RS) because RS is given and it is not bypassed.

Av=-1.5×3.3KΩ/ (1+1.5×1)

Av=-2.