Introduction: Proximity Sensor With 2N7000 Mosfet

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FET Proximity Sensor

This very simple proximity detector circuit will sense over 1 meter range with very few components. Output can be modified to drive a relay, power transistor or mosfet .

Step 1: For Maximum Sensitivity, R2 Should Be of a Large Value ( in the 1000 Mohm Range ) . You Will Have to Make It.

Step 2: You Will Need : 1) a Match 2) a Small Length of Wire. Wind Wire Tightly on Both Ends of Match to Form the Resistor. You Can Paint the Resistor With Clear Nail Polish to Protect From Moisture.

Step 3: Transistor Q2 Amplifies FET Current to Drive LED.

Step 4: Calibrate Potentiometer VR1 for Minimum Brightness of LED. Watch Video for More Details.

Step 5: