 The ignition coil is the source of high voltage needed to make current bridge the gap of the spark plug in the combustion chamber. It is a pulse-type transformer, and here’s how it works:
Inside the coil case are two sets of windings: the primary, several hundred turns of heavy wire; and just inside it, the secondary, several thousand turns of fine wire. These are wrapped around an iron core in the center. When battery current is conducted through the primary winding, a strong magnetic field develops around the iron core. When the flow of current is interrupted, the magnetic field collapses across the secondary winding.
As the secondary winding has more turns than the primary, high voltage is induced into the secondary winding. This high voltage then shoots out of the center terminal of the distributor, which is attached to the iron core.
The customary ways in which current flow is broken are by contact breaker points, or in later cars by an electronic switching device inside the distributor. |
