Question

Consider the circuit shown. VDS=3 V. If IDS=2mA, find VDD to bias circuit.

(a) -30V

(b) 30V

(c) 33V

(d) Any value of voltage less than 12 V

I had been asked this question by my school principal while I was bunking the class.

This interesting question is from Biasing of JFET and MOSFET topic in division FET Amplifiers of Analog Circuits

Answer 1

Right choice is (c) 33V

The explanation: VDS = VDD – IDS(10k + 5k)

3 = VDD – 2(15)

3 = VDD – 30

VDD = 33 V.