| 摘要 |
PURPOSE:To automatically re-light up a fluorescent lamp which has gone in stall immediately by making variable the inductance of each choke coil with control windings, controlling it, and changing the resonance frequency of a series resonance circuit consisting of the choke coil and a capacitor. CONSTITUTION:According to the inductance characteristics of a choke coil winding 37 when a DC current is sent flowing through a control winding 41 of a variable inductor, the inductance is decremental with incremental amperage. The DC control of the variable inductance of each series resonance circuit is made by a DC control circuit 24, and the same current control is performed by connecting in series a plurality of control windings. The inductance is transferred to L0 to generate resonance condition by dropping the current periodically below the resonance point control amperage i0 while the lighting period is controlled to a DC amperage i1 so that an inductance L1 some lower than the resonance point inductance L0 is generated. Thereby a fluorescent lamp which has gone in stall, is immediately re-lighted up automatically. |
