In the classic three op-amp instrumentation amplifier, the differential voltage gain is usually produced by the:
A)second stage.
B)output op amp.
C)mismatched resistors.
D)first stage.

Question

Quizplus · Accepted Answer

The differential voltage gain is usually produced by the first stage of the instrumentation amplifier, which is a difference amplifier. The two input signals are applied to the non-inverting and inverting inputs of the first op amp, and the output is the amplified difference between the two signals. The second stage is a non-inverting amplifier with a gain of one, which provides a high input impedance and low output impedance for the overall circuit. The output op amp is used to buffer and amplify the signal, but it does not contribute to the differential voltage gain. The use of matched resistors is important for minimizing common-mode noise and improving the common-mode rejection ratio (CMRR) of the amplifier.

In the Classic Three Op-Amp Instrumentation Amplifier, the Differential Voltage