Question

If the doping concentration of the gate increases, the internal pinch-off voltage ___________

(a) Increases logarithmically

(b) Increases linearly

(c) Increases exponentially

(d) Decreases linearly

This question was addressed to me during an online interview.

I'd like to ask this question from Characteristics of JFET topic in portion FET Amplifiers of Analog Circuits

Answer 1

Correct choice is (b) Increases linearly

To elaborate: The internal pinch-off voltage is linearly proportional to the doping concentration. Hence, it would increase with the increase in the doping concentration. The built-in-barrier potential is logarithmically proportional to the doping concentration of the gate.