| 摘要 |
PURPOSE:To make a display of a reception frequency easy to see all day long by controlling the brightness of a reception frequency display element according to adjustments of the illumination intensity regulator of a car and by increasing the brightness of the display element when a lighting switch is turned off. CONSTITUTION:When lamp switch 3 is turned on, lamp 5 and incandescent electric lamp 11 are turned on with a voltage regulated by illumination-intensity regulator 6 and through transistor TRs 17, 23, 24, 29, and 31, vehicle-mounted radio reception- frequency display LED12 is turned on. As regulator 6 is adjusted to increase the voltage applied to lamp, the brightness of LED12 increases and as the application voltage to the lamp, the brightness of LED12 increases. When the lamp is turned off with switch 3, the base voltage of TR17 drops and while TRs 17 and 23 turn off, TRs 29 and 31 turn off, maximizing the brightness of LED12. Thus, the display of the reception frequency becomes easy to see without reference to the ON-OFF state of switch 3. |
