Quote:
Originally Posted by Dave in Boise
Here's my take.. Very simple
a) coils for 12 volt non ballasted ignition circuits ---- will show 12 v out when put from one terminal to the other
b) coils for 6 volt ignition circuits ---- will show 6v out when 12v is put in one side
c) coils for 12 volt ignition circuits with a ballast resistor ---- will show 6v out when 12v is put in one side due to the internal resistor
d) so-called sports coils for 12 volt circuits ---- will show 12 v out when put from one terminal to the other.
Hope this Helps.
Dave
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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.