Question

Find out the gain value  by which each input of the averaging amplifier is amplified ?( Assume there are four inputs)

(a) 0.5

(b) 0.25

(c) 1

(d) 2

I got this question in a job interview.

Asked question is from Summing, Scaling & Averaging Amplifier in division Operational Amplifier Applications of Linear Integrated Circuits

Answer 1

Accurate choice is (b) 0.25

Breaking it down, I'd say: In an averaging amplifier, the gain by which each input is amplified must be equal to lower number of input.

=> RF /R =1/n , where n=number of inputs

∴ RF /R=1/4 = 0.25 (Four inputs)

So, each input in the averaging amplifier must be amplified by 0.25.