The switch function is made up of a neon gas discharge tube and a capacitor in parallel, so that the two touch plates do not produce sparks during separation to avoid burning the bad contacts, prolong the service life of the starter, and also reduce the interference to the nearby radio equipment.
When the switch is connected, the supply voltage is immediately added to the poles of the starter by ballast and lamp filament. The voltage of 220 volts immediately causes ionization of the inert gas of the starter to produce glow discharge. The heat of glow discharge causes bimetallic sheets to expand and contact with two poles. The current passes through the ballast, the starter contact pole and the ends of the filament to form a passage.