Which component is NOT part of a spark ignition system?

The thermostat is not part of a spark ignition system. In a spark ignition system, the primary components work together to create and manage the ignition of the fuel-air mixture. These components include the ignition transformer, which converts low voltage into high voltage to create a spark, the electrode, which generates the spark itself, and the cable, which connects the transformer to the electrode.

The function of the thermostat, while essential to the overall heating system, is primarily to regulate the temperature by controlling the activation of the heating system. It senses the ambient temperature and signals the system to turn on or off as needed, but it does not directly participate in the ignition process, making it distinct from the other components associated with spark ignition.