TJ-56-520 Metal detector scanner unassembled kit

The metal detector DIY welding kit uses high-quality circuit boards and components to form a high-frequency oscillation circuit and a detection circuit. When the detection coil is close to a metal object, the buzzer sounds, simulating the working principle of a metal detector. This product is small and easy to carry. There are not many components and it is easy to weld. Suitable for students or electronics enthusiasts.

Kit parameters:
Power supply voltage: 5~12V (DC power supply)
Board size: 70*61mm
Measuring distance: 5cm (related to the size of the measured object)

Product Description:
Q1, L1, L2, C1, C2, R1, and RP form a high-frequency oscillation circuit, adjust RP to make the oscillation circuit in a critical state, that is, make the oscillation circuit in a state of just starting to oscillate, Q2 and Q3 form a detection circuit, and the circuit oscillates normally When the AC voltage generated by the oscillation exceeds 0.6V, Q2 will be turned on in the negative half cycle, and C4 will be discharged and short-circuited, so that Q3 will be cut off; when the detection coil is close to the metal object, an eddy current will be generated in the metal conductor to make the energy in the oscillation circuit The loss increases and the vibration stops, so that Q2 is cut off, and C4 is charged through R2, and Q3 is turned on to push the buzzer to sound. According to whether there is a sound, it can be judged whether there is a metal object under the detection coil.

Commissioning method:
Products L1 and L2 are directly made on the circuit board without self-made, and the assembly is completed according to the component list. The power supply can be 5-12V DC. The positive pole of the power supply is connected to VCC, and the negative pole is connected to GND. Slowly adjust the adjustable resistance RP until the buzzer sounds, then adjust RP in the opposite direction until the sound just stops. Use iron objects to approach the coil on the circuit board, and the buzzer will sound, indicating success.