Ignition coils are inductive components transforming low-voltage DC current from the vehicle’s electrical system into the high-voltage pulse needed to create an arc at the spark plug gap. These coils are utilized in both distributor-based and distributorless ignition systems, and can be individually mounted on spark plugs (coil-on-plug) or as part of a coil pack serving multiple cylinders. Primary windings create a magnetic field when energized, and rapid collapse of this field, controlled by the Ignition Control Module (ICM) or Engine Control Unit (ECU), induces a high-voltage pulse in the secondary winding. Modern coils frequently incorporate internal igniters and utilize materials optimized for high dielectric strength and thermal conductivity. Failure modes typically involve open or shorted windings, or igniter malfunction, resulting in misfire or no-start conditions.