| 摘要 |
A voltage reduction unit for reducing the voltage supplied to a lighting element to a prescribed value and for maintaining the prescribed voltage across the lighting element independently of the current flowing through it. A lighting element is connected in series with a current switch, and the current switch is controlled by a voltage/current control unit which monitors the lighting element for changes and voltage and current characteristics. The voltage/current control unit comprises a differentiator circuit for detecting a slope of an AC voltage waveform and a comparator circuit for detecting a prescribed voltage on the waveform. The voltage/current control unit allows current to flow through the lighting element when both a first prescribed voltage and a prescribed voltage slope of the voltage waveform is detected, and it inhibits current flow through the lighting element when a second prescribed voltage is detected. A signaling circuit receives signals from the comparator circuit and the differentiator circuit, and it communicates switching signals to the current switch for rendering the current switch conductive when signals representing the prescribed voltage and slope of the voltage waveform occur. When the comparator detects the second prescribed voltage, it emits a second signal, and the signaling unit, in turn, communicates a signal for turning off the current switch.
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