The reason why the ignition coil can turn the low voltage on the car into high voltage is that it has the same form as an ordinary transformer, and the turns ratio between the primary coil and the secondary coil is large. However, the working model of the ignition coil is different from that of the ordinary transformer. The ordinary transformer works continuously, while the ignition coil works intermittently. It repeatedly stores and discharges energy at different frequencies according to the engine's different speeds.
When the primary coil is connected to the power supply, a strong magnetic field is generated around it as the current increases, and the iron core stores magnetic field energy; when the switch device disconnects the primary coil circuit, the magnetic field of the primary coil decays rapidly, and the secondary coil A very high voltage will be induced. The faster the magnetic field of the primary coil disappears, the greater the current when the current is disconnected, and the greater the turns ratio of the two coils, the higher the voltage induced by the secondary coil.