摘要 |
The invention is directed to a circuit and a method for efficiently controlling the output illumination level of a gas discharge lighting arrangement having four or more gas discharge lamps with multiple ballasts. Load side control of each ballast is provided by a timed interval controlled impedance, serially coupled between the particular ballast and its associated lamps. A circulating inductor, coupled in parallel with each controlled impedance, provides a current path between the power source and the lamps at least during that portion of the AC waveform when the controlled impedances are non-conducting. The invention is equally operable at both 120 volt and 277 volt AC levels without major component changes.
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