ignition coil questions

Don't overlook the role of the condensor in the Kettering ignition.

If you really want to learn about transistor switches for the coil circuit, buy a Velleman ignition & build it yourself. For about 20 bucks you can say you made your own electronic ignition:

http://www.vellemanusa.com/downloads/0/illustrated/illustrated_assembly_manual_k2543.pdf

And if you blow it up you can fix it too. Not clearly mentioned in the instructions is how it limits current. That TIP162 is a fast darlington, and it handles the current limit in the low side of the coil.

I have one of those units on a 6v tractor, that has been running for decades. Can't do that with a GM module.

B.