> >Right. I thought you were saying that there's a situation where Q2 >wouldn't turn off. "might not". If Q1 in the on state isn't fully saturated, then you may get base current through Q2. That's where the diode between CQ1 and BQ2 comes in. >Correct, this turns on Q2 and activates the relay. Again I thought you >were talking about Q1 activated and Q2 maybe not going off. Yes. >It did no problem. And everything turns off when Q1 is active. Well, you have to check that carefully, you could be just off the edge, or well in. Measuring the base current, and the voltage on Q1C would be a good step. -- Dave's Engineering Page: http://www.dvanhorn.org Where's dave? http://www.findu.com/cgi-bin/find.cgi?kc6ete-9 -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads