POWER CONTROL APPARATUS WITH OPTICAL ISOLATION FEEDBACK MEANS

摘要

The invention comprises transformerless power supply apparatus particularly adapted for supplying regulated power to critically sensitive loads such as tungsten lamp filament loads of designed power rating. Power control is achieved by a triggered triac in series with the load, and regulation is provided by a feedback circuit, voltage or current, which generates the triac trigger signal periodically as a function of the load voltage or current. The feedback circuit is provided with a photo isolator for eliminating premature triggering of the triac due to transients. A timing circuit is also provided for timing the power on condition, the output of which is photo isolator coupled to the triac feedback circuit.