Question

The configuration in which voltage gain of transistor amplifier is lowest is ____________

(a) common collector

(b) common emitter

(c) common base

(d) common emitter & base

The question was posed to me in a national level competition.

I need to ask this question from Comparison of Transistor Amplifier in division Small-Signal Low-Frequency AC models of Transistors of Electronic Devices & Circuits

Answer 1

Correct choice is (a) common collector

To elaborate: In common collector configuration (also known as the emitter follower) because the emitter voltage follows that of the base. Offering a high input impedance and a low output impedance it is extensively used as a buffer. The voltage gain is unity, even though current gain is high. The input and output signals are in phase.