At 04:11 PM 8/9/99 -0700, you wrote: >Thanks to everyone who has offered an opinion on this topic! > >> I have read the responses to this, but firstly I must ask why turn the >> power off? Why not use the power down and sleep function in the PIC? > >Because asleep, with the WDT running so it can wake itself periodically, the >current drain is (data sheet worst case) about 10uA. Which would only give >me a couple of years even on the fattest coin cell readily available (250mAH >or less), and the person who's asking my help wants four or five years. So >I thought I'd better kick around some zero-power ideas. Take a look at a 9-volt lithium battery in standard transistor radio style. 1200 mAH. The battery may die of old age before you deplete it at a few uA. About 14 years at 10 uA, battery shelf life is ten years. Standard (cheaper) alkaline should get you five years. Kelly **************************************************************************** ******** All legitimate attachments to this email will be clearly identified in the text. William K. Borsum, P.E. OEM Dataloggers and Instrumentation Systems &