| 摘要 |
838,517. Discharge lamp circuits. THORN ELECTRICAL INDUSTRIES Ltd. June 7, 1957 [June 20, 1956], No. 19172/56. Class 38 (4). In a fluorescent lamp circuit of the type comprising a choke, a cathode heating autotransformer and a power factor correcting capacitor, wherein a discharge is initiated across the lamp electrodes when cold to remove remanent charges from the tube wall, the capacitor, whose initial charging current initiates the surge, is arranged to be fed from a tap on the transformer to limit the applied voltage. A fluorescent lamp 20 is connected to a supply 10, 15 through a choke 11 and autotransformer 13. Power factor capacitor 17 is connected across the supply terminal 10 and a tap 16 on autotransformer 13, the tap position being arranged so that less than mains voltage appears across the capacitor. Other arrangements are given in the Specification suitable for very short and very long lamps, low-voltage supplies, and twin lamp arrangements. |
