How to use an automotive ignition coil

Dumbascii · Posted: 08/30/2007 18:48 PM Post subject:

This is the ignitor used in my Taternator II. It can be made from cheap junkyard parts, any old mechanical ignition. When the button is pressed, current is sent to the coil through the normally-closed relay contacts. The relay is energized at the same moment, breaking the circuit to the ignition coil a split second later. The coil generates a spark when the magnetic field collapses. The condenser shunts the flyback voltage to ground, minimizing arcing inside the relay. The spark is beefy enough to jump three 1/8" gaps in series and is very reliable even under hybrid pressures. The battery does not need to be a car battery - just 12V.

Edit: added photo below. Notice that the cases of the coil and condenser are well connected to the chassis. Sorry for the crappiness of the phto of the back of the control panel - it is difficult to reach without dismantling.