Elektronisches Vorschaltgerät für eine Gasentladungslampe

摘要

In electronic ballasts for gas discharge lamps (3) which consist of a bridge rectifier (1) to be connected to the a.c. mains and a converter (2) connected downstream thereof, the brightness of the lamp may flicker, which is particularly annoying with the lamp (3) dimmed. To prevent this flicker, it is opposed that the operating potential terminal (mass) (6) inside the circuit be connected in the a.c. manner to the protective earth (S) of the a.c. mains. A second method may consist in connecting the internal reference potential terminal (mass) (6) to the phase terminal (L) and/or the neutral terminal (N) or with one or both of input terminals (10, 11) of the bridge rectifier (1) in the a.c. manner. In a third method, the a.c. "hot" output terminal of the bridge rectifier (1), which is connected to the internal reference potential terminal (mass) (6) via a smoothing capacitor (C4), is to be connected in the a.c. manner to the protective earth (S) of the a.c. mains. Yet another method is to screen the lines (15-18) leading to the lamp (3) and to connect the screens (15, 16, 17, 18) to the circuit-internal reference potential terminal (mass) (6).