| 摘要 |
PURPOSE:To stabilize the maintenance of lighting of a fluorescent lamp with respect to fluctuations of temp. and voltage by inserting a diode between the cathode of a thyrister and the non-power supply negative electrode side. CONSTITUTION:An AC power supply E increases to increase the voltage between both electrodes of a fluorescent lamp, while the voltage of a resistor R2 in a normal direction with respect to a serial diode D4 and a divided voltage of a resistance R1 flow, through a diode D2, in the following order, a condensor C3 SCR gate G its cathode K diode D3, and thereby every cycle SCR is energized, while a preheating current flows, then a fluorescent lamp is put into operation untill charging of condensor is completed. The condensor C3 is thereafter stabilized during lighting operation, but the sensitiveness of the SCR gate G is increased widely according to the rise of circumferential temp. In this case, it is possible to stabilize the operation level of the SCR gate G, that is the operation of SCR with respect to the temp. fluctuations by inserting the diode D3 into a charging circuit. |
