| 摘要 |
PURPOSE:To provide a device which performs a reliable display of a speed during a running even if a key switch is brought to OFF, by a method wherein, in a speed display device for electrically displaying a speed of a vehicle, after a power supply switch is shifted to opening from closing, and a running of a vehicle is detected by means of an output signal from a speed sensor to keep a feeding to the speed display device in case the vehicle is in a running condition. CONSTITUTION:If a key switch 2 is closed, electricity is fed to a speed display device 10, and a constant-voltage circuit 4 outputs driving circuit 7. The speed computing circuit 6 computes a speed after counting an output signal from a speed sensor 5 at each unit time, and outputs it to the display driving circuit 7 to drive a display element 8. If a key switch 2 is closed, in case a speed signal from the speed sensor 5 is generated, a feeding needs to continue. If the speed computing circuit 6 detects a speed signal from the speed sensor 5 and decides that a vehicle is during running, with a switch activated, electricity is fed to the speed display device 10 from a power source 1 through a switch 3, and thereby, even if the key switch is opened, a feeding continues to perform a display. |
