| 摘要 |
PURPOSE:To prevent the unnecessary flow of electric current to a light emitting element when a device is not working and to save the electricity by providing a control circuit which allows the current to flow only when the device is working between a light protect and an index detection light emitting element and a power source. CONSTITUTION:When a motor-on signal is not inputted to a control terminal 1a, the control circuit 1 keeps on 'off', and as the unnecessary current is not supplied to light emitting diodes 2a, 3a, the waisting of the power is prevented. Next, when the motor-on signal is inputted, the control circuit 1 is turned on, the current is supplied to LEDs 2a, 3a, and light protect detection and the index detection is executed. When phototransistor Tr2c, 3c detect the light emitted from LEDs 2a and 2b, the light protect signal and the index detecting signal are outputted from output terminals 2c, 3c. |
