| 摘要 |
PURPOSE:To prevent generation of core noise by supplying signals for generating a high brightness of a fluorescent lamp and maintaining a discharge alternately from an inverter. CONSTITUTION:A pulse generator 11 generates pulse signals with pulse signals changed by adjusting a changeable resistance 10. The signal from the generator 11 is applied to a gate of a PNP transistor(Tr) 25 through an NPN Tr 20, PNP Tr 20, and an amplifier 24. A base voltage of the Tr 25 becomes strong when the pulse signal is at level '1', and it is low when it is at level '0'. When the low base voltage is supplied, the Tr 25 is saturated, and it shows a high resistance for the high base voltage. An inverter 3 generates signals for generating a high brightness at a fluorescent lamp 37 and maintaining a discharge alternately corresponding to an output of the Tr 25. Dimming is thus achieved without putting the fluorescent lamp 37 off, and change of a magnetic flux is reduced, thereby noise of a core is restricted. |
