As the Common mode voltage gain decreases, the CMRR ________.

Question

Question

This question was previously asked in

DFCCIL Executive S&T 2016 Official Paper

Answer 1

Explanation:

CMRR:.

Common Mode Rejection Ratio (CMRR) is defined as the ratio of differential-mode gain to common-mode gain taken in magnitude

CMRR stands for Common Mode Rejection Ratio It is the ability of an operational amplifier to reject the common-mode signals at the input terminals

Mathematically, this is expressed as:

\(CMRR = \frac{A_v}{A_c}\)

Av = Differential gain

Ac = Common mode gain

Hence if Common mode gain(A_c) decreases, CMRR increases.

Important Points

For practical operational amplimers, The Common Mode Rejection Ratio (CMMR) should be 80 to 100 dB.

For Ideal operational amplimers, The Common Mode Rejection Ratio (CMMR) should be infinity.