The lowest power low frequency oscillators are probably LC ;-) But in real life a sawtooth oscillator or blocking oscillator implemented with a logic level fet and pulse transformer will probably do it imho. If I'm not wrong this uses only 5 parts. Ask me again for a schematic. Peter -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu