At 04:48 PM 2/10/03 -0500, Jim Ruxton wrote: >Thanks everyone for the creative solutions for controlling a bleeder >resistor. I may give Russels suggestion a try first since I wouldn't >have to add a relay to my board. Thanks again. >Jim I can suggest an even simpler idea: use a small MOSFET with an appropriate voltage rating. Use your AC input (before the rectifier) as a small capacitively coupled charge pump that is continually keeping a capacitor on the gate of the FET discharged. When the AC disappears, the gate capacitor charges and the FET turns on. Depending on what DC supply you have available for the gate supply, you may want a zener clamp to ensure that the gate voltage does not exceed 20V. Total parts: couple of diodes, couple of small capacitors, zener, resistor, FET, bleeder resistor. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 18 years of Engineering Innovation (1984 - 2002) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu