Instrumentation Amplifier

Experiment 10

Aim:

To design and construct Instrumentation Amplifier Circuit using Op-amp IC.

Apparatus Required:

Theory:

An instrumentation amplifier is a type of differential amplifier that has been specifically designed to have characteristics suitable for use in measurement and test equipment. These characteristics include very low DC offset, low drift, low noise, very high open-loop gain, very high common-mode rejection ratio, and very high input impedances. They are used where great accuracy and stability of the circuit both short-term and long-term are required. The most commonly used instrumentation amplifier circuit is shown in the figure.

The ideal common-mode gain of an instrumentation amplifier is zero. In the circuit shown, common-mode gain is caused by mismatches in the values of the equally numbered resistors and by the non-zero common mode gains of the two input op-amps. Obtaining very closely matched resistors is a significant difficulty in fabricating these circuits, as is optimizing the common mode performance of the input op-amps

Design

Circuit Diagram

Observations

Procedure

1. Construct the circuit as per Circuit diagram shown in figure.

2. Switch ON IC Power Supplies and apply the Input Voltages at Non-inverting input terminals.

3. Observe the Output Voltage using Digital Multimeter for different input voltages.

4. Note the readings and verify its values with theoretical calculation.

Link to experiment

Go here and select Experiment 10

Demonstration Video