| 摘要 |
PURPOSE:To prevent overheating with a simple circuit and a simple element by connecting thermostats into driving circuits of power transistors of an inverter circuit. CONSTITUTION:Thermostats 31 are provided in the vicinity of, or coming in contact with the heating parts 19 and 20 of an inverter circuit 8. The thermostats 31 are connected into driving circuits of power transistors 6 and 7 of the inverter circuit 8 for being made an LC resonance circuit and a parallel lighting circuit. Accordingly, when discharge lamps 21 and 22 come to the end of their life and filaments are broken, the circuit of only L is left and voltage to be impressed on the discharge lamps 21 and 22 drops so as to stop discharge for preventing discharge and to prevent generation of an accident such as in case of a linear lighting method, further, in case of not starting at the time of preheating, the thermostats 31 operate to stop oscillation. Thereby, a simple circuit and a simple element can prevent overheating. |
