| 摘要 |
PURPOSE:To light a fluorescent lamp at the time of a low temperature or a low voltage by repeating action of reducing a capacitor potential of a timer circuit, and switching on a transistor again when the fluorescent lamp is not lighted by a pulse for one time. CONSTITUTION:When a power supply voltage is at a positive cycle, a transistor 13 is put on to preheat a preheating electrode of a fluorescent lamp 3. At a time set by a timer circuit, a thyristor 10 gets on, while the transistor 13 gets off, and a stabilizer 2 generates a pulse voltage to light the lamp 3. When a lighting determination means comprising resistances 17, 18 determines that it is not lighted, a diode 9 and the thyristor 20 get on to discharge charges of an electrolytic capacitor 8 to get off a diode 9 and the thyristor 10, while the transistor 13 gets on again. By thus repeating on/off action of the transistor 13, preheating of the lamp 3 and pulse voltage generating action are repeated to light the lamp 3. The fluorescent lamp 3 can thus be started even at the time of a low temperature or a low power supply voltage. |
