| 摘要 |
PURPOSE:To make the start of a fluorescent lamp impossible when its light flux is largely reduced. CONSTITUTION:A device is provided with a series circuit composed of a stabilizer 2 connected to an AC power supply 1 and a fluorescent lamp 3 having a pair of preheating electrodes 4, 5; a transistor 7 in which a collector and an emitter are connected to each other between the preheating electrodes of the fluorescent lamp 3 on the non-power supply side through a diode 6; and a timer circuit 16 composed of a resistor 8 to be actuated by a voltage between the collector and the emitter in the transistor 7, and a capacitor 9 comprising an electrolytic capacitor having temperature dependency and having equivalent life characteristics to those of the fluorescent lamp 3. In addition, it is provided with a thyristor 10 to switch the transistor 7 by a capacitor voltage of the timer circuit 16, a transistor base drive control means 17 comprising a Zener diode 11 and a resistor 12, and a serial circuit of a resistance 18 and a surge absorber 15 provided between the collector and the emitter of the transistor 7. |
