| 摘要 |
PURPOSE:To light surely an operation display light when a proximity object approaches by constituting separately a transistor (TR) turning on/off the operation display light through the output of a comparator and a TR to which an output changeover switch is connected. CONSTITUTION:When a changeover switch SW is turned off and an output of the comparator CP is turned on (an object to be detected approaching), the TRs TR1, TR4 are both turned on, a current flows to a resistor R7 and a light emitting diode LED and the light emitting diode LED is lighted. Further, a current flows also to a resistor R4' and a TR2 is turned on. When the comparator CP is turned on with the switch SW turned on, the TRs 4, 1 are both turned on, the light emitting diode LED is lighted and an output signal of the TR4 turns on a TR3 for controlling the oscillation difference and the oscillating condition of an oscillating circuit 1 is brought strict, thereby preventing the repetition of unstable state where the oscillation stopped once is restarted and stopped because of the detection of an approaching object. Then, the approaching output of the object to be detected is led out as an ON signal or an OFF signal by the turning on/off of the changeover switch in this way. |
