| 摘要 |
PURPOSE:To always control the illuminance of a lamp by making variable a duty ratio of a pulse signal issued from an illumination control device by means of a variable resistor and lighting an illuminating lamp for a vehicle meter via an amplifying circuit. CONSTITUTION:Turning on an ignition switch 7 causes power supply to be applied to an illumination control device 3. And, a pulse signal changed in its duty ratio by adjusting a variable resistor VR1 is inputted to a transistor T1 of an amplifying circuit 4 via a resistor R1, and the illuminance of an illuminating lamp 5 of a car meter is controlled by the above-mentioned pulse signal inverted by a next stage transistor T2. When a lighting switch 2 is turned on, the illuminating lamp 5 of the car meter is directly lighted via an OR circuit 6. Hereby, the illuminance of an illuminating lamp of meters can be always controlled. |
