| 摘要 |
A single-ended ballast circuit employs a power-factor-correcting network (510); a DC power supply (512); a free-running oscillator (516); a transistor (518); a current-limiting (ballasting) network (520); and two fluorescent lamps (524). The transistor (518) is configured as a switch connected to be responsive to a signal generated (630) by the oscillator (516) and operative to periodically couple a line (734) to a circuit common. The current-limiting (ballasting) network (520) includes an inductor or transformer (740) having a primary winding (744), connected between a DC power-supply potential and the line (734), and a secondary winding (746); a first capacitor (750), connected between the line (734) and circuit common; an inductor (752); a second capacitor (756), connected in series with the inductor (752) across the secondary winding (746); and a third capacitor (754), connected in series with the lamps (524) across the second capacitor (756).
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