Question

Which of the following is true for the voltage gain (AV) for the common source configuration (represented by A1) and the common gate configuration (represented by A2)?

(a) A1 = A2

(b) |A1| = |A2| and A1 ≠ A2

(c) |A1| > |A2|

(d) |A1| < |A2|

This question was addressed to me in quiz.

This intriguing question originated from Basic MOSFET Amplifier Configurations topic in portion MOS Field Effect Transistors (MOSFETs) of Electronic Devices & Circuits

Answer 1

Correct answer is (b) |A1| = |A2| and A1 ≠ A2

For explanation: A1 = -gm(RL||RD) and A1 = gm(RL||RD)

Reference figure for common source configuration

Reference figure for common gate configuration