| 摘要 |
PURPOSE:To display speeds accurately as far as a vehicle is under traveling even if a key switch is turned off by continuing the supply of electric power to a speed display when the output signal from a speed sensor indicates the vehicle under traveling. CONSTITUTION:The transistor of a holding means 8 is turned on and a relay switch 81 is turned on by the high level output when the speed from a judging part 205 of an arithmetic processing unit 2 is in excess of 0km/h during traveling of a vehicle. Then, even if the driver disconnects and contacts an electric power source 9 by connecting the key switch 7 to contact OFF or ACC on a downgrade or the like, electric power is supplied from the power source 9 to a constant voltage circuit 8 through the means 8, and the speed display by a display 5 is continued. Therefore, even if the key switch is turned off, the speed is displayed accurately as far as the vehicle is under traveling. |
