Re: Ignition Coil Problem
I'll expand on the description for anyone interested;
An ignition coil is a step-up transformer, that gets pulses of 12 volts (or less) in the primary coil winding. The ends of that coil of wire are the + and - terminals.
During "start" 12 v is applied to the + from the start solenoid circuit, the - wire goes to the points and then to engine ground when the points close. Current flows in ~100 turns of primary wire, causing a magnetic field to build up. The magnetic field also goes through several thousand turns of very fine wire that makes up the secondary of the coil.
One end of the secondary is common to the - terminal, the other goes to the HV tower in the middle of the coil.
That induces a voltage in the secondary turns of less current but much greater voltage.
The magnetic field continues to build while the points remain closed, (dwell). Then the points open, the magnetic field collapses very fast, inducing a lot of voltage in the secondary, 6000 to 8000 v. That's more than enough to jump the small gap in the distributor and the spark plug back to ground.
When the key is released to "on", the coil + is supplied by a wire with resistance in it, to limit current and not cook the coil.
The condenser is across the points to absorb the voltage generated in the primary from the collapsing field. Without it, points would last only a couple hours.
