| 摘要 |
PURPOSE:To obtain a stable output with a lower power-source voltage by installing a control circuit which does not operate an apparatus at a power-source voltage or less which causes erroneous operation. CONSTITUTION:When light is irradiated into a light receiving circuit 2, and a power-source voltage VC lowers and each standard voltage VR<+>, VR<-> becomes nearly equal, an output generates chattering, since the hysteresis effect due to a resistor Rf is not developed in the state where the power-source voltage VC is low. Therefore, each electric current of photodiodes 10 and 11 is detected by a resistor 12, and the apparatus is controlled so that an output V0 is not operated in the state where the power-source voltage VC is low. For example, when the power-source voltage VC lowers below 2.5V, and the voltage VB applied onto the resistor 12 becomes below a standard value VB (e.g., 1V), the base current of a transistor 43 is ccontrolled by turning ON a diode D2 by a control circuit 4, and the operation of the output V0 is obstructed. |
