On Mon, Jan 24, 2011 at 1:52 AM, Richard Prosser wrot= e: > Yep, that pretty much describes the operation. It was originally > intended as a relay drive circuit to allow 24V relays to operate from > a 12-15V supply. Once pulled in the standing current was enough to > hold the relay in. Not recommended for critical applications however! > > As only a quick pulse of energy was required in this case I thought it > may be applicable. =A0Q1 can be just a mechanical switch if required and > the "off" current is effectively zero once C1 is charged. Cool idea, thanks Richard! Josh --=20 A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. =A0 =A0 =A0 =A0 -Douglas Adams --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .