Optically isolated line voltage sensing circuit

摘要

A linear optocoupler is employed to provide a signal which is a galvanically isolated reproduction of the magnitude of an A.C. line voltage and another galvanically isolated signal indicative of a change in the polarity of the line voltage for enabling safe monitoring of a change the A.C. voltage. Actuation of an automatic transfer switch to substitute an emergency source of power for a normal source that has failed may be achieved with the emergency power waveform used to replicate the normal power waveform.