| 摘要 |
A dimmer for a fluorescent lamp comprising a ballast inductor and an impedance adjuster for connecting impedances of various values between a power source and one of the lamp filaments, the other lamp filament being connected through a starting switch to the one lamp filament and to the power source. The value of each impedance connected is such that it will allow a current sufficient to start the lamp to pass therethrough. A circuit is provided for increasing the impedance between the inductor and the lamp, upon starting of the lamp, to reduce the current from a level sufficient to start the lamp to a level below the minimum required to start the lamp but above the minimum required to maintain the lamp emission once started, whereby a reduced light intensity level is produced. In another embodiment the ballast inductor has an impedance such as would draw, during starting, a current greater than the maximum rated current capacity of the lamp filaments. A resistance impedance element having a resistance which would during starting, reduce the current through the filaments to a current not greater than the maximum rated current capacity thereof is connected in series with the starting switch between the two lamp filaments whereby during operation after starting the light intensity level of the fluorescent lamp is greater than would be produced at a current not exceeding the maximum rated filament current.
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