| 摘要 |
<p>PURPOSE:To improve the operability by selectively connecting two attenuators in series to a luminaire in accordance with brilliance in the outside, so as to automatically switch an adjusting range of lighting brightness, in a lighting dimmer for adjusting brightness of the luminaire in accordance with brilliance in the outside. CONSTITUTION:A lighting dimmer is applied to a black face meter for illuminating instruments of an automobile or the like by a back light source. Now in the daytime, when an ignition switch SW3 is turned on, since a transistor Tr1 is turned off, each transistor Tr2, Tr3 is turned on. As this result, brightness of a lighting lamp 3 is adjusted by a variable resistor VR. In the case of turning on a light switch SW2 in the daytime, when a changeover switch SW4 is turned on, brightness of the lighting lamp 3 can be adjusted. Further, when the light switch SW2 is turned in the nighttime, each headlamp 6 is lighted to turn on the transistor Tr1. As the result, brightness of the lighting lamp 3 can be adjusted by a dropper resistor DR.</p> |
