| 摘要 |
PURPOSE:To light fluorescent lamps different in wattage with a single lighting device by changing the lighting frequency of a switching transistor and the impedance of a current limiting means according to a detected lamp voltage. CONSTITUTION:The resistors 28, 29 of a lamp voltage detecting means consisting of the resistors 28, 29, a capacitor 30 and zener diodes 26, 27 and transistors 18, 20 are ON/OFF according to the detected lamp voltage of a fluorescent lamp 10 to change the lighting frequency of a switching transistor 6. Consequently, the impedance of a current limiting inductance 11 is changed to change the magnitude of the lamp current carried to the lamp 10. According to this constitution, the lamp 10 can be lighted with the optimum lamp current by changing the lamp current according to the wattage of the lamp 10, and a plurality of fluorescent lamps different in wattage can be lighted under optimum lighting conditions with one lighting device. |
