Amplifier Provides Signal Conditioning for Piezofilm Sensor

Abstract: Described circuit provides a thermal output from a piezofilm transducer. The circuit is a high-input-impedance differential charge amplifier using three op amps in a somewhat classical instrumentation amplifier configuration. The differential stage rejects resistor-generated thermal noise, and acts as a first-order high-pass filter. Choice of component values is discussed, and some typical valuese are suggested. Alternate configurations are suggested for overcoming some typical circuit limitations.