On Fri, Mar 7, 2014 at 10:32 PM, IVP wrote: > I wrote this page many years ago, includes a lifetime vs voltage graph > > http://home.clear.net.nz/pages/joecolquitt/0bulblife.html That graph illustrates the rule of thumb that has stuck with me ever since I first heard it. Basically, a 5% change in voltage either halves or doubles the life of the bulb (depending on which way you're changing the voltage). Pretty neat! Josh --=20 A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .