Question

What is the role of emitter bypass capacitance in the transistor amplifying circuit?

(a) To prevent damage of emitter resistance from variation in voltage

(b) To prevent emitter from over voltage

(c) To increase gain

(d) To increase load to transistor circuit

I have been asked this question in quiz.

Question is taken from Characteristics of Amplifier in division Transistor Biasing and Low Frequencies of Analog Circuits

Answer 1

The correct choice is (c) To increase gain

The explanation: When an emitter resistance is added to the amplifier circuit, in common emitter mode, voltage gain is reduced and input impedance increases. When we need to obtain higher gain, we add a capacitance in parallel to the emitter resistance, called emitter bypass capacitance, and voltage gain does not decrease.