Tony wrote... >As part of my circuit, I used a relay to convert a full wave rectified >AC input to a half wave to detect when the "time set" switch is pressed. >This is just a series diode being switched in and out of a leg of the AC >path to the full wave rectifier. Relay... Ugh. Click, click. Bad. >Is there a way to do this without a relay? Yes. The series diode that you're switching in and out with that mechanical... "thing" could be replaced by a power mosfet. When its gate is biased so as to turn the mosfet ON, it conducts current on both halves of the cycle; when the gate is biased to turn it mosfet OFF, it conducts only in one direction, through the intrinsic substrate diode. Whether you use a p-channel or n-channel device, which direction you face it, and how to arrange the gate drive are all things that depend on the circuit details. DD -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu