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. The usual ignition coil has two sets of coils, a primary coil and a secondary coil.
Ignition coils are divided into open and closed magnetic types according to the magnetic circuit. The traditional ignition coil is an open magnetic type. Its iron core is made up of 0.3mm silicon steel sheets, and the secondary and primary coils are wound around the iron core. Closed-magnetic type uses the core of the shape of III around the primary coil, and then the secondary coil around the outside, the magnetic flux lines from the core constitute a closed magnetic circuit. Closed-magnetic ignition coils have the advantages of low leakage flux, small energy loss, and small size. Therefore, closed-magnetic ignition coils are commonly used in electronic ignition systems.