The usual ignition coil has two sets of coils, a primary coil and a secondary coil. The primary coil uses a relatively thick enameled wire, usually about 0.5 to 1 millimeter around the enameled wire around 200-500 turns; the secondary coil uses a thin enameled wire, usually about 0.1 mm around the enameled wire around 15000-25000 turns. One end of the primary coil is connected to the low voltage power supply (+) on the vehicle, and the other end is connected to the switching device (breaker). One end of the secondary coil is connected with the primary coil, and the other end is connected with the output end of the high voltage line to output high voltage electricity.
The reason why the ignition coil can change the low-voltage electricity in the vehicle to a high voltage is that it has the same form as an ordinary transformer, and the primary coil has a larger ratio of turns than the secondary coil. However, the working mode of the ignition coil is not the same as the ordinary transformer. The working frequency of the ordinary transformer is a fixed 50Hz. It is also called the power frequency transformer, and the ignition coil works in the form of a pulse. It can be seen as a pulse transformer, which is different according to the engine. Speed is repeatedly stored and discharged at different frequencies.