| 摘要 |
PURPOSE:To prevent the heat generation and ignition by breakage of a transistor by connecting a temperature fuse in series to the transistor, and disposing this temperature fuse close to the transistor. CONSTITUTION:A closed circuit is formed of an AC power source 1, a stabilizer 2, and a fluorescent lamp 3. A noise preventing capacitor 4 is connected to both the ends of the fluorescent lamp 3, and the collector terminal and emitter terminal of a transistor 13 having a base circuit for conducting switching by a timer circuit formed of a resistance 6 and an electrolytic capacitor 8 are connected to the non-power source side preheating electrode terminals of the fluorescent lamp 3. A temperature fuse 14 is connected in series to the transistor 13, and this temperature fuse 14 is disposed close to the transistor 13. Thus, even if the transistor 13 is broken and obtains a resistance value to generate heat, it is cut at a set temperature by the temperature fuse 14. Hence, the heat generation and ignition by breakage of the transistor can be prevented. |
