摘要 |
An electrical circuit for operating an electrical discharge lamp has a pair of terminals for connection to a supply of voltage of substantially sinusoidal waveform, a second pair of terminals for connection with a discharge lamp, a ballast impedance connected between one of the first pair of terminals and one of the second pair of terminals, a starting device for aiding initiation of discharge in the lamp and means for disabling the starting device when a discharge has been initiated in the lamp. The means for disabling the starting device operates in response to a change in the voltage waveform across the second pair of terminals from substantially sinusoidal to substantially square. |