What is the function of the inductor coil in the pulse metal detector?

What is the function of the inductor coil in the pulse metal detector?

The pulse metal detector is a commonly used tool for detecting metal objects, and is widely applied in fields such as archaeology, geological exploration, and metal detection.

The working principle of the pulse metal detector is as follows: The pulse signal generated by the host drives the transmitting coil to produce a powerful and short pulse current. This is equivalent to a hollow coil that can generate a magnetic field. If a metal object appears inside or near this hollow coil, the alternating magnetic field will induce eddy currents on the metal. The reflected signal is received by the receiving coil, processed, analyzed and amplified, thereby determining the position and depth of the metal item.

The inductor coil is the core component of the pulse metal detector. It is responsible for emitting electromagnetic waves and receiving reflected signals. The transmitting coil, which constitutes the main body of the detector, is wound around by a multi-core cable. The number of turns is usually between 6 and 7.

The receiving coil is used to receive the reflected signals. It usually employs a small-diameter coil with a large number of turns, typically ranging from 200 to 300 turns. This helps to enhance the sensitivity and resolution of the coil. The inductance value of the receiving coil is generally low because it needs to be able to receive small signals.

In the design of pulse metal detectors, the shape and number of turns of the coil are not fixed. The size and shape of the inductive coil will be optimized according to the different application scenarios of the detector. The size of the detection coil can be determined based on the unit area being detected. Generally speaking, the closer the shape of the coil is to a circle, the better the detection depth and sensitivity will be. However, some pulse metal detectors are in the form of a square ring, rectangular ring, circular ring, polygonal ring, or even an irregular ring.

For instance, in deep detection scenarios, larger coils need to be used to increase the detection depth; while in indoor detection situations, smaller coils are required to enhance the detection sensitivity.

The coil design of the pulse metal detector is a complex issue that requires considering the influence of multiple factors in order to design a coil with high sensitivity and high resolution.