Precision rectifier for digital voltmeters

This simple circuit, based on a single opamp in non-inverting mode, is a precision rectifier extension for digital voltmeters. The circuit can be connected to a high-impedance voltage-divider without the need of an additional buffer stage that increases the cost and, more importantly, the power consumption. Another advantage of this circuit is that the accuracy is not affected by the offset volta ge of the opamp. The output of the rectifier is differential to allow ready connection to the IN-LO and IN-HI inputs of DVM ICs like the familiar 7106 and similar types.