Wiring Schematic Diagram

This metal detector circuit diagram is based on the IC TDA0161, designed for metallic body detection by detecting the variations in high frequency Eddy current losses. For detecting metals , TDA0161 require an external LC tuned circuit .

Output signal is determined by supply current changes. Independent of supply voltage, this current is high or low according to the presence or the absence of a close metallic object. This medal detector circuit use two LEDs , which offer an visual indication of presence or absence at a metals ,around the coil . To adjust the circuit you need to make sure there is no metal near the coil and then set the fine adjustment to a "Mid position". After that you need to adjust the course adjustment to turn on the LED and , adjust the fine adjustment to turn off the LED.

This metal detector electronic circuit operates over a wide range input voltage of 4 -35 volts . If you want you can use other values for the Cx capacitor and for L1 inductor ( changing this value will affect the frequency oscillation and the detection range ).