Electronic control circuit for discharge lamp - includes semiconductor switch between two storage capacitors switched at higher frequency than that of alternating supply

摘要

The control circuit provides power for discharge lamps such as those containing mercury vapour, sodium, neon or metallic iodides. The circuit includes a first capacitor serving as a reservoir of energy provided by the alternating supply network. A second capacitor serves as the source of current for the lamp itself. A bi-directional controlled semi-conductor switch is connected in series between the two capacitors to allow or prevent the flow of current from the first to the second capacitor. A control circuit regulates the alternate closing and opening of the switch at a frequency much higher than that of the supply. A current limiting inductance is also connected to the first capacitor.