Sensitive wideband linear a.c.-d.c. convertor

A theoretical and experimental study of a simple but effective linear a.c.-d.c. convertor circuit is presented. A fullscale sensitivity, without preamplification, of 200 mV r.m.s. has been achieved with an absolute accuracy of within approximately ±3%. However, after calibration, the circuit can maintain an accuracy of within 1% over the temperature range 10¿50°C. The frequency response is flat to within 0.2 dB from 20 Hz to 10 MHz and to within 3 dB from below 10 Hz to approximately 80 MHz.