| 摘要 |
<p>PURPOSE:To make dimming of a plurality of illuminating systems in harmony with the illumination of an illuminative type display device of a car by performing control via a Zener diode of a voltage corresponding to the supplied voltage difference of a transistor in the system of an illumination element having a high supply voltage. CONSTITUTION:The output of a Rheostat controller 1 to control the brightness of an illuminating type display device of a car is integrated by an integrator circuit 2 installed in a radio set, etc., and converted into an analog voltage. With this voltage a transistor 17 an illumination element system of LED's 25, 35 having a low supply voltage is controlled, while a transistor 7 of an illumination element system of LED's 5, 15 having a high supply voltage is controlled with a conversion voltage which is passed through a Zener diode 6 corresponding to the voltage difference between the two systems. Thereby a plurality of illuminating systems are dimmed to a brightness in good harmony with the illuminance of the display device of car.</p> |
