| 摘要 |
PROBLEM TO BE SOLVED: To continuously control the quantities of light from a combination meter and an interior illumination lamp day and night through the operation of a single member. SOLUTION: At daytime running where an ignition switch SW1 is turned on, a driving voltage or battery voltage is inputted through the switch SW1 and a diode D1 into a chopper control circuit 121, which in turn outputs a switching signal S to switch over a current-control transistor Tr21. A current correspondingly flows through the switch 21, a meter lamp LM, a transistor Tr12 and the transistor Tr21 to the ground to bring the lamp LM on and thus a combination meter 110 backlit, which makes meter-indication characters visually recognized. At nighttime running, a driving voltage is inputted through the switches SW1 and SW2 and the diodes D1 and D2 into the chopper control circuit 121, which in turn outputs a switching signal S to switch over the current-control transistors Tr21 and Tr22. |
