Posted by David Sherman on Wednesday, July 10, 2002 at 3:34PM :
In Reply to: Conversion from 6 volts to 12 volts posted by Matt Wilson on Tuesday, July 09, 2002 at 9:35PM :
The thing from radio shack is probably a voltage regulator with a part number like "7806" or "LM340-6". It has a metal tab with a hole in it, a square blob of black plastic, and 3 flat wires sticking out of the end opposite the tab. It will work but may be fragile for automotive use. If you accidentally hook the polarity up backwards it will probably explode like a firecracker. They do protect themselves against a short-circuit in the gage circuit and against getting too hot. I don't know if the JC Whitney ones are any better or if they're just the same gizmo stuck in a more rugged package.
For a fuel gage you can get by with just a resistor if you are able to experiment with different values until you find the one that give you close to 6V in your system. I don't know about the temp and oil pressure gages, if yours are electrical. The ammeter doesn't care.
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