The schematic , capacitor 70 circuit from 2008, according to past references, seems to allow passage of power supply 6A DC current to pass through spark plug when 24kv ignition fires. The toroid transformer of the circuit works ok on high v. side. Others have reported this circuit as working. I am wondering now, exactly how the route is for the 24kv through the output end of the 18vDC power supply that has bridge rectifier 1kv diodes of 4, AC non polarized polypropylene capacitor used as filter, with optional safety spark gap 75v + protective varistor. This design circuit is to NOT USE a protective 30 diodes string bank that loses 21v voltage drop and causes higher input battery draw to power supply Inverter to DC, to overcome the loss because of having a needed increased secondary voltage. I also have insulated high v cable on both ferrite toroid ring transformers to prevent spark over. There is to be an ISOLATED INVERTER TO DC source that is not affected by the incoming high voltage pulses, but allows the passage of 24kv back up to fire spark plug. Diodes and capacitors generally fail due to heat. There is no heat with a high voltage line. (Maybe the end capacitor could be rated as AC 30kv as high quality polypropylene and NOT used as a proper filter capacitor. Would the millisecond's hi v pulse pass through?
Suggestions needed to help me understand the flow path on power supply side.

 

I looked at that circuit and evidently a great deal of power is coming from the alien life form in the middle. Rather much beyond my understanding., to my dismay.

 

Mystery to me as well. All I know is that a 100V-rated transistor won't last long driving an automotive ignition coil.

 

REALLY, to push six amps thru a spark plug will take a monster 24 Kv supply, even if that is only for a millisecond. But the voltage will not need to be 24 KV once the ark is struck. So there will not be any switching of power sources It can easily be done with a capacitor bank. And once the arc is struck the voltage will be less than 100 volts across a NON-RESISTOR spark plug, where I=V/R, and V= 24KV, until the capacitors discharge a bit.