Switched series startup resistor? (in parallel with run-feed) Minimal dissipation in switch. IF 12V rail sags below xx turn on hard. If above xx + delta_yy turn off. Resistor takes the heat. R --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .