According to the magnetic circuit, the ignition coil is divided into two types: open magnetic type and closed magnetic type. The traditional ignition coil is of open magnetic type, and its iron core is made of silicon steel sheets of about 0.3 mm, and the secondary and primary coils are wound around the iron core. The closed magnetic type uses an iron core similar to III to wind the primary coil, and then winds the secondary coil outside, and the magnetic field line is formed by the iron core to form a closed magnetic circuit.
