10.4.4 Ignition coil
In essence, the ignition coil is a transformer, which converts the low voltage from the on-board power supplies (12 V) into a voltage, which is sufficient for producing a powerful spark between the electrodes of the spark plug needed to ignite the fuel-air mixture inside the engine cylinder. Sufficient voltage is 20-30, or even 60 thousand volts.
For this type of conversion in there are two windings - primary and secondary, as well as the core the body of the coil. Each winding has a different number of threads and wire cross sections. When you turn the key and turn on the ignition from the battery pack, an electric current is applied to the primary winding and through the contacts it is closed to "ground". When a current pass through the primary winding, an electromagnetic field is created around the coil. As soon as the contacts open and the current flowing through the primary coil stops abruptly, the required voltage and current will appear in the secondary coil. And already current in 30 and more thousand volts from a secondary winding of the ignition coil will flow through the distributor to a spark plug.
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