| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting system where fusing of a filament on one side of a discharge lamp is detected. SOLUTION: One end of an auxiliary winding of a reactor L2 is connected to the anode of a diode D, and the other end is grounded. A series connection circuit, comprising resistors R1, R2, and R3, is connected between a cathode of the diode D and the ground. A capacitor C3 is connected between the connection part of the resistors R2 and R3 and the ground, and the connection part of the resistors R2 and R3 is connected to a base of a transistor TR1. A resistor R4 is connected across both ends of the filament of a fluorescent lamp K in parallel. A series circuit of consisting of resistors R5 and R6 is connected between one end of the resistor R4 and the ground. A collector of a transistor TR is connected to one end of the resistor R6 and emitter is connected to the other ground side of the resistor R6. An output signal of a detecting circuit M is outputted from the collector of the transistor. |
