Question

What is the problem with a single operational high frequency response of differential amplifier?

(a) High input resistance

(b) Low input resistance

(c) Low output resistance

(d) High output resistance

I have been asked this question in an internship interview.

Question is taken from High Frequency Response of the Differential Amplifiers topic in section Frequency Response of Electronic Devices & Circuits

Answer 1

Correct option is (b) Low input resistance

Easy explanation: The problem with a single operational high frequency response of differential amplifier is its low input resistance. This low input resistance results in a loss of a major component of the signal. Operational Amplifier is internally a High frequency response of differential amplifier with features like High Input Impedance, Low Output Impedance.