The circuit below shows a difference amplifier using an op amp. It presents an impedance of R1 to each end of the sensor (VSEN+ - VSEN-). The gain transfer function of the difference amplifier is also shown in the figure.
- Resistive isolation from the source
- Large input voltage range is possible
- Reject common mode noise; it's good for remote sensors
- Resistive loading of the source
- Input stage distortion