Question

For an RC coupled common source JFET amplifier without bypass capacitor, find the voltage gain if gm = 1mΩ^-1, source resistance is 2kΩ, drain resistance is 15kΩ and load is 10kΩ.

(a) -2

(b) -2.5

(c) 5

(d) 2

I have been asked this question in examination.

My enquiry is from JFET Amplifier topic in section FET Amplifiers of Analog Circuits

Answer 1

The correct option is (a) -2

For explanation I would say: AV = -gmRL’/1+gmRS

RL’= 15k|| 10k = 6kΩ

AV = – 2.