The usual ignition coils have two sets of coils, primary and secondary. Primary with a thicker enameled wire, usually with a 0.5-1 mm around the enameled wire around 200-500 turn around, secondary with a finer enameled wire, usually with a 0.1 mm around the enameled wire around 15000-25000 turn around. The primary one end is connected with the low voltage power supply (+) on the car, and the other end is connected with the switch device (power off device). The secondary one end is connected with the primary, and the other end is connected with the High-voltage output end to output high-voltage.
The reason why the ignition coil can turn the low-voltage electricity into the high voltage is due to the same form as the common transformer, and the primary is larger than the secondary. But the ignition coil works the same way as the ordinary transformer, ordinary transformers operating frequency is fixed 50Hz, also known as power frequency transformers, and ignition coil is the pulse of the form of work, can be seen as a pulse transformer, depending on the engine speed at different frequencies of energy storage and energy can be repeated.
When the primary is plugged in, a strong magnetic field is produced as the current grows for four weeks, and the iron core stores the magnetic field energy; When the switching device causes the primary circuit to disconnect, the primary's magnetic field decays rapidly and secondary induces a very high voltage. The faster the magnetic field disappears, the larger the current is, the greater the primary of the two coils, the higher the voltage of the secondary sensor.