A method of improvement of the low-cost rectifiers performance in wideband AC voltmeters and amperemeters

Abstract

Low cost AC voltmeters and amperemeters usually suffer from dependence of their rectifier parameters on the measured quantities - amplitude and frequency. Special rectifier topologies have been created in order to improve the rectifier behavior. In this paper another approach is discussed. This approach is based on the fact the rectifier is operated with only single amplitude for which it is frequency compensated. The logical circuits, which can be replaced with a microcontroller, set the preamplifier gain in that way the desired reference voltage was reached. Then, the displayed value does not refer to the measured value but to the preamplifier gain setting step. However, this value can be easily converted to match the measured value. Copyright © (2012) by the International Measurement Federation (IMEKO).