Spark Plug: Description and Operation

Spark Plug View:

The spark plugs provide the gap across which the high tension voltage jumps, to create the spark that ignites the compressed air-fuel mixture. The center electrode is insulated from the spark plug shell by means of a porcelain insulator. The side electrode protrudes from the bottom edge of the spark plug shell. It is positioned so that there is a gap between it and the center electrode.