Deve,
Two main things going on with ignition system:
1) Controlling the coil to make a spark. This involved sending voltage to the coil and cutting it off repeatedly. Sending voltage through the primary windings (an ignition coil is a transformer with at least two windings) creates a strong magnetic field (read about: flux). Removing voltage suddenly collapses the field and INDUCES a voltage in the secondary windings of sufficient strength to jump a plug gap.
2) Delivering the spark at the right time to match up with the state of the cylinder (compression stroke, at XX degrees of engine rotation). (read about: ideal ignition timing and fuel charge burn rates in combustion engines)
The points based ignition system (also known as a Kettering system) has the points doing BOTH. When closed, they are passing current directly to the coil to build the mag field. When opened at the right time, based on the profile of the point cam, it delivers the spark at the right TIME.
In a contactless system (aka electronic system) the coil controller or ignition module controls the coil while the trigger mechanism controls the timing. Of course this is an oversimplification, most modern electronic systems also make timing decisions and only use the trigger or sensor to understand the rotational position of the engine.
Good reading here:
http://books.google.com/books?id=-Y...ignition%20systems%20concept&f=falseIn an earlier post I believe you commented about a "correct" setup that uses a primary resistor with the coil. It is a planned compromise, not the ideal solution. That resistor is there to protect the points, not the coil. The coil would tolerate much higher voltages in most cases. The points would burn up too quickly to be feasible though. This is one of the benefits of electronic ignition: higher coil voltages and faster rise times. Rise time is the time it takes to establish the magnetic field in the coil. This time is what determines what the maximum rpm is that can be supported by the ignition system before it becomes weak or unstable.
Jason
Deve, BTW, sending me a person message that suggests I may be "one of those internet weenies who just goes with the flow and dismisses people with a desire to make a distinct difference in this community" is not a great way to enlist someone's help. I took the time I have in giving this information for the benefit of everyone here who might care.
