Question

For the difference amplifier which of the following is true?

(a) It responds to the difference between the two signals and rejects the signal that are common to both the signal

(b) It responds to the signal that are common to the two inputs only

(c) It has a low value of input resistance

(d) The efficacy of the amplifier is measured by the degree of its differential signal to the preference of the common mode signal

I got this question in an international level competition.

My question is from Difference Amplifiers topic in chapter Operational Amplifiers of Electronic Devices & Circuits

Answer 1

Correct choice is (a) It responds to the difference between the two signals and rejects the signal that are common to both the signal

The best explanation: All the statements are not true except for the fact that it responds only when there is difference between two signals only.