Abstract

Many engineers face the challenge of amplifying small signals produced by sensors with high source impedance in a low-noise circuit. Amplifier circuit design for sensor applications such as hydrophones, guitar pickups, high source impedance microphones, and turntables can benefit from a combination of discrete components and operational amplifiers. This application note discusses the use of JFET and Operational Amplifiers (op amps) in a composite amplifier configuration to accomplish this design challenge.