How can I use the voltage generated from inductive kickback?
How can I use the voltage generated from inductive kickback?

The current flowing through an inductor, upon closure of switch contacts, would result in energy being stored in its magnetic field. Disruption of the current, caused by the switch contacts opening, would lead to a collapse of the magnetic field and consequent induction of a high voltage that would spark across the open contacts to transfer energy back to the source.
Should that inductor form the primary of an ignition coil with a turns ratio of 1:100, the voltage of around 200 V induced by it would be stepped up by the secondary to around 20 kV and fed to the spark plug via a high tension cable.

A capacitor across the contacts would provide a path for the induced current to to weaken the spark and minimizing pitting.
In a capacitor discharge ignition system, a capacitor, charged to a high voltage would be discharged through the primary of the ignition coil to generate extra high voltage at the secondary.