Three Op amp Instrumentation Amplifier

Three Op amp Instrumentation Amplifier:

The commonly used Three Op amp Instrumentation Amplifier circuit is one using three op-amps. This circuit provides high input resistance for accurate measurement of signals from transducers. In this circuit, a noninverting amplifier is added to each of the basic difference amplifier inputs. The circuit is shown in the Fig. 2.51 (a).

Three Op amp Instrumentation Amplifier

Three Op amp Instrumentation Amplifier

The op-amps A1 and A2 are the noninverting amplifiers forming the input or first stage of the instrumentation amplifier. The op-amp A3 is the normal difference amplifier forming an output stage of the amplifier.

The block diagram representation of the three op-amp instrumention amplifier is shown in the Fig. 2.51 (b).