Mazda 80W glass starter switch.

Part of the Bob Gray collection of electrical objects.

A starter switch strikes a high voltage electric arc between a pair of electrodes within a tube containing mercury vapour. An initial surge of energy is required to start the arc. Once the arc is established, the inside of the tube, coated with fluorescent powder, produces light through the action of the arc. Starter switches were designed to be replaced easily as they inevitably failed after a few thousand cycles. Until the early 1990s they were required to turn on fluorescent lamps.