For us old enough to remember turning on a fluorescent lamp and waiting a few seconds for the lamp to flicker and come on – this is the circuit. Cold weather made longer delay and many lamp flickers while warming to operating temperatures. You knew lights needed to be better than daily ordeal.
The Starter switch (top SPST) starts lamps (current through bulb filaments to heat filaments to a dull red) and after the tube lights (arc strikes) - then manually or automatically opens starter switch which does no further work. The Starter switch could be taken out of the circuit with lamp ON and fluorescent tube would stay lighted.
Ballast (shown as current source) limits the current to amount required by lamp starter switch during the start up.
Radio Interference was controlled by moving radio or small capacitor across the power line to the fluorescent lamps.
