Question

Bandwidth of amplifier is __________

(a) Difference between upper cut-off frequency and lower cut-off frequency

(b) Sum of upper cut-off frequency and lower cut-off frequency

(c) Average of upper cut-off frequency and lower cut-off frequency

(d) Independent to cut off frequency

This question was posed to me at a job interview.

Origin of the question is General Frequency Consideration in division Transistor Biasing and Low Frequencies of Analog Circuits

Answer 1

Right option is (a) Difference between upper cut-off frequency and lower cut-off frequency

Explanation: 3dB bandwidth of an amplifier is the difference between upper cut-off frequency and lower cut-off frequency. The unity gain bandwidth is the difference between frequencies where gain is 1.