Question

How is it possible to vary the voltage from closed loop gain to the open loop gain?

(a) By using differential amplifier with larger gain

(b) By using differential amplifier with small gain

(c) By using differential amplifier with variable gain

(d) By using differential amplifier with differential gain

The question was asked in homework.

My question comes from Differential Amplifiers with Multiple Op-Amp in section Operational Amplifier Characteristics of Linear Integrated Circuits

Answer 1

The accurate option is (c) By using differential amplifier with variable gain

Discover the easiest explanation: Variable gain in differential amplifier can be obtained by using a potentiometer. So, depending on the position of the wiper in potentiometer, voltage gain can be varied from the closed loop gain to the open loop gain.