Proximity Sensor With 2N7000 Mosfet

by simpletronic in Circuits > Electronics

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Proximity Sensor With 2N7000 Mosfet

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 .

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

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.

Proximity Sensor With 2N7000 Mosfet

Proximity Sensor With 2N7000 Mosfet

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

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.

Transistor Q2 Amplifies FET Current to Drive LED.

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