Instrumentation Amplifiers

The circuit below shows an instrumentation amplifier that conditions a remote voltage sensor. The input resistors provide isolation and detection of the sensor open-circuit failure. It amplifies the input difference voltage (VSEN+ - VSEN-) and rejects common mode noise.

in-amp.png

Advantages:

  • Excellent rejection of common mode noise, e.g. great for remote sensors
  • Resistive isoloation from the source
  • Detection of sensor failure

Disadvantages:

  • Resistive loading of the source
  • Higher cost

Sensor Examples:

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