| Topic | Summary |
| Battery power source |
A battery is used to supply a voltage to the system components. |
| Ballast resistor |
The ballast resistor is used to reduce the voltage to the ignition coil during normal running conditions. |
| Ignition coil |
The ignition coil is a step-up transformer. It increases the battery voltage to provide a spark for ignition. |
| Ignition switches |
The common points on an ignition switch include: Lock, Off (not on all vehicles); Accessories, On and Start. The key can only be removed from the 'Lock' position. |
| Contact breaker |
The contact breaker is a mechanically operated electrical switch in the primary ignition circuit. The contacts open and close automatically with engine rotation. |
| Capacitor/condenser |
A capacitor or condenser is used to assist in the rapid collapse of the magnetic field in the ignition coil. |
| Distributors |
The distributor in a contact breaker system distributes the high-tension voltage surges to the spark plugs in the correct sequence and at the correct instant in time in the engine cycle. |
| Distributor types |
There are several different distributor types including: kettering system, pulse generator, hall effect generator, electronic and optical sensor unit. |
| High-tension leads |
High-tension leads are used to transmit the high voltage required by the spark plugs to ignite the fuel/air mixture in the cylinders. |
| Spark plugs |
Spark plugs deliver the spark that initiates combustion in an engine cylinder. They are identified by thread size or diameter, the reach or length of the thread, and by their heat range. |
| Spark plug components |
The main spark plug components are a threaded metal case with a ceramic insulating covering, a sparking tip with an adjustable spark gap, center and side electrodes and a terminal to connect the plug to the ignition system. |
| Advance & retard mechanisms |
Ignition timing can be varied by a centrifugal advance mechanism, according to engine speed and by a vacuum advance unit according to engine load. |