Sean Breheny wrote: > Hmmmm, well, I suppose that WOULD work given the example I gave, but > let me change it a bit > What about a device which draws 1 amp normally? You would at least > need a bigger bulb (to prevent it from lighting, resistance > increasing, and dropping significant voltage)! Firstly name me an appliance that draws one amp at 3V and may be damaged by reverse polarity? For 6V (may be tricky) and certainly 12V, you use automotive lamps. > I do have to admit that I didn't think of the bulb. It's terribly elegant isn't it? In one fell swoop, it's extremely cheap and readily available, has exactly the desired characteristic and is rated to dissipate the heat. -- Cheers, Paul B.