Metal detectors usually have three useful techniques:
Very low frequency (VLF), also known as inductive balance, is probably the most commonly used exploration technique today. The elf metal detector has two different coils:
Transmitting coil - outer loop coil. Inside is a coil made of wire. The device declares that the current changes thousands of times per second along the direction of wire replacement and change. The number of changes in the direction of the current per second constitutes the frequency of the probe.
Receiving coil - the inner coil of the is composed of another coil wound with wires. This coil can be used as an antenna to collect and expand the electromagnetic wave frequencies announced by the underground policy object.
The current flowing through the transmitting coil generates an electromagnetic field, just as an electric motor generates the same electromagnetic field. The polarity of the magnetic field is straight on the coil position plane. Whenever the current changes direction, the polarity of the magnetic field changes accordingly. This means that assuming that the coil is parallel to the ground, the direction of the magnetic field will constantly change, falling on the ground and rising on the ground.
As the direction of the underground magnetic field changes repeatedly, it will interact with any conductor strategy object encountered, resulting in a small magnetic field generated by the strategy object itself. The polarity of the magnetic field of the strategy object is completely opposite to that of the transmitting coil. Assuming that the direction of the magnetic field generated by the transmitting coil is vertically upward and downward, the magnetic field of the strategic object is vertically upward on the ground.
The receiving coil can completely shield the magnetic field generated by the transmitting coil. But it will not shield the magnetic field of underground policy targets. Therefore, when the receiving coil is above the strategic object transmitting the magnetic field, a small current will appear on the coil. The current vibrates at the same frequency as the magnetic field of the strategy object. The receiving coil will extend the frequency and transmit it to the console of the metal detector, and the components on the console will analyze the signal.
According to the magnetic field intensity generated by the strategic object, the metal detector can approximately determine the buried depth of the strategic object. The shallower the strategic object is buried, the stronger the magnetic field collected by the receiving coil,
