Older car coils (for use with mechanical points) typically draw about 3 to 4 amps at 13v, and are driven from close to 50:50 duty cycle. They will also stand 13v for 100% of the time if your car stalled with th epoints closed....
I dont have much experience with automobile coils so i dont know how much
leakage they design in at the factory nor how much primary resistance there
is. The primary resistance may be set to limit current in the event of saturation.
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