Question

A p-channel  Ge JFET has max-half channel width 5µm and channel conductivity of 2/Ωcm, if Er = 2000cm^2/Vsec, What is the value of pinch off voltage?

(a) 8.21V

(b) 82.1V

(c) 88.21V

(d) 5.2V

I had been asked this question in a national level competition.

The question is from The Pinch off Voltage Vp in division Field-Effect Transistors of Electronic Devices & Circuits

Answer 1

Right answer is (c) 88.21V

Best explanation: Vp=qNA a^2/2E

= (5×10^-4) (5×10^-4)×2/(2×16×8.854×2000×10^-14)

= 88.21V.