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Old 11-02-2011, 08:21 AM   #24
MrTube
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Default Re: 12 volt or 6 volt coil how to tell difference

Quote:
Originally Posted by Tom Wesenberg View Post
You need current flow to get a voltage drop. If you apply x volts in you will get x volts out without current flow.

I find 12 volt coils are marked 12 volts on the case, but this still doesn't tell you if it should have an external resistor. I'd connect the voltage across the 2 primary termianls to determin if it needs an external resistor. If the coil draws about 3 to 4 amps then it shouldn't need an external resistor. If it draws more amps, then add a resistor to bring the current draw down to 3 to 4 amps.

BTW, the markings "DIST" and "BAT" on the coil primary termianls are useless unless you know what the coil was built for as far as battery ground.
So does this all mean its just easier for most people to throw out unknown coils and simply buy a coil for the proper application?
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