The back EMF pulse from an ignition coil primary (-) side switched on/off to ground by a GM HEI module is about 30nS wide and maybe 300 volts tall. Current flow starts out at about 5 amps. The other side of the coil is connected to the (+) power rail of the car through 5 ft of #18 wire to the battery and alternator.
How does the wire and battery/alternator appear to the back EMF pulse? At that short of a duration is it a low impedance path to ground or (+) 12v?
How does the wire and battery/alternator appear to the back EMF pulse? At that short of a duration is it a low impedance path to ground or (+) 12v?