What is the working principle of an ignition coil?

[DelMila]

Here is a brief introduction about automotive ignition coils: 1. The automotive ignition coil essentially applies the principle of an electromagnetic induction transformer. The only difference between an ignition coil and a transformer is that a transformer operates continuously, whereas an ignition coil works intermittently. The ignition coil repeatedly stores and releases energy at a certain frequency, depending on the engine's operating speed. 2. When the ignition system's switching device connects the primary coil (low voltage), the current flowing through the low-voltage coil magnetizes the iron core, creating a strong magnetic field around it, and the iron core stores this magnetic energy. Then, when the switching device disconnects the primary coil circuit, the magnetic field of the primary coil disappears instantly, the iron core demagnetizes, and the magnetic lines of force rapidly contract, cutting through the secondary coil (high voltage). This induces a very high voltage in the secondary coil.