> I do not like these circuits, since you get a serious heat source, in > that 100K resistor. There was a work-around circuit, described here: > http://www.edn-europe.com/improvedoptocouplercircuitsreducecurrentdrawres= istledaging+article+2021+Europe.html Thanks, I'll add that link=20 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .