I've heard this talked about here, but how real is it? In cars from 1964 to 2006, I've had all sorts of devices on the 12v system, most without any fancy protection, and many fairly sensitive, and none ever suffered. I would think the lead acid battery would sink any spike that came along and the worst you might get is some hf noise far from the battery. Off hand, I can't think of any switched inductances or capacitance that would cause it, and even then, it would have to be far from the battery I'd guess. Is it a myth? luis antonio prata barbosa wrote: > The "Load Dump" fenomenum makes car voltage up to 80v or higher. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist