| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting device capable of producing at a low cost without decreasing reliability. SOLUTION: When a fluorescent lamp FL is lit in full light, a switch SW1 is opened. Base current is supplied to a base of a transistor Q3, the transistor Q3 is turned on, the input voltage of an oscillation control circuit 5 is decreased, an inverter circuit 4 is outputted according to the rated value in the high output of the fluorescent lamp FL, and a full light output state is set. When the fluorescent lamp FL is lit in modulated light, the switch SW1 is closed. The base current of the transistor Q3 is bypassed with the switch SW1, and current from an auxiliary power source 6 is supplied to the switch SW1. The transistor Q3 is turned off, the input voltage of the oscillation control circuit 5 is decreased, the inverter circuit 4 is outputted according to the rated value in the rated output of the fluorescent lamp FL, and a modulated light output state is set. |
