On Wed, Mar 5, 2014 at 8:06 AM, Dwayne Reid wrote: > All of the Variacs that I have used have two input terminals / taps: > one gives you zero to full input voltage; the other input tap gives > you zero to about 115% of input voltage. That is: 115Vac input, zero > to 140Vac output. > > Its easy to open up the Variac case and change taps if needed. The problem with that one was that it was configured as 0-140VAC from the factory, and no one looked at it. An extra 15% line voltage definitely shortens lamp life in a dramatic fashion. I used to have a slide rule put out by a bulb company (probably by Osram or Ushio) that let you calculate this. 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 .