Conventional rectifiers employing diodes can’t be used with low-amplitude signals. This Idea for Design describes a circuit using Analog Devices' AD844 op amps to create a mixed-mode precision ...

You can combine a carefully chosenop amp, a low-thresholdP-channel MOSFET, and two feedbackresistors to make a rectifier circuit withless forward drop than a diode (Figure1). The rectified output ...

This design idea shows an unconventional precision full-wave rectifier circuit with a notable lack of matched resistors.