Metal detectors are devices that can detect metals. The usage area is quite wide. It helps us in military mines, weapons searches, concert, airport and shopping center body searches, finding harmful items, archaeological and geological excavations. In this content, we will talk about the structure and working principle of the metal detector.
Detectors are devices that work with radio frequency. The coils on it form the receiver and transmitter part. When the electromagnetic wave produced in the emitting part encounters a metal, a current is induced on the metal (faraday currents - eddy currents). The current induced on this metal produces a magnetic wave, allowing current to flow through the receiver coil on the detector. The obtained signal is strengthened with the help of an amplifier, giving an audio signal and visual notification. Depending on the detector power, it can search up to 12 meters.
► The position of the coils on the detector heads should be adjusted well. As a result of faulty production, the coils detect each other and the detector works incorrectly.
► Depending on the type and size of the metal, there may be different perceptions in the magnetic field, the larger the surface of the metal, the shorter the detection time.
► Some minerals in the soil may cause the conductivity of the soil to increase and the metals to oxidize and decrease their metallic properties.
► Natural gas, water pipelines, electrical cables may lead the detector to false detection.
Detector Types
 ► Low frequency oscillator detector (VLF)
► It is the most used detector type. There are two coils. Receiver and transmitter coils.
► Pulse frequency detector(PI)
► It is mostly used in sensitive works. There is only one coil. The depth measurement range is wide. It is used in salt water, mineral soils.