Electrically isolated signal transmission interface - is esp. for AC signals and has bridge rectifier coupled to optically isolated coupler

摘要

An electrically isolated interface between an electronic circuit and a load uses a bridge circuit and opto coupler to provide fast operation coupled with a low power loss. The a.c. signal which may be in the range 110 to 380V, 50 or 60 Hz, is connected to inputs with a phase shift resistor (5) and capacitor (4). The signal is summed by a diode bridge (1a, 1b) and is rectified (1c) before processing over a filtering capacitor (6). A resistor (8) determine the operating current for the light emitting diode of the opto coupler (7). Through use of a small caparitor (4) the LED attains full intensity in a short period resulting in his speed transmission across the unit.