Ignition Capacitor is a principal component of the high-tension magneto system. The essential parts of a magneto for a multicylinder automobile are : Spark Plug, Distributor, High Tension Coil (HT Coil), Contact Breakers (CB Point), Capacitor (Condenser)and Battery. For a single cylinder two wheeler kick start magneto system, Magnet and Coil replace the Battery while the Distributor is absent.
An Ignition Capacitor works essentially as a spark quencher. Every time the contact breaker opens, the current in the primary circuit is abruptly broken resulting in heavy sparking across the CB points. The Capacitor connected across the CB points absorbs this spark energy and thus ensures that the CB points do not get pitted and worn out. The life of the contact breaker is very limited in the absence of the Capacitor, while the presence of the right Capacitor extends its life immensely.

The Capacitor working in the inductive circuit also fulfils another important function. The spark across the CB points has to be quenched fully or else the current in the primary circuit does not rupture abruptly. Only when the current ruptures suddenly does the HT coil deliver a very high voltage kick in its secondary. Thus, the choice of the capacitance value should be right and the Capacitor must be of a very high quality to result in a very powerful spark at the spark plug.

To sum up, the functions of a Capacitor are:
1. To quench the sparking at the contacts and hence ensure a long life for the CB point.
2. To enable a high induced voltage in the secondary thus resulting in a powerful spark at the spark plug.
Thus, the optimum performance of an automobile demands the choice of the best quality Ignition Capacitor.