If you will mention the words metal detector to people, you will surely get different reactions and this is because people see the use metal detectors in different ways. For example, it is usual for airport security personnel to use handheld scanners on passengers and it is common for security guards to comb spectators’ bodies before the concert. For people who frequent the beaches they can also imagine people combing the sand with their metal detectors trying to find lost coins or jewelleries that fall off from the bathers. Since all these events are usual this makes metal detecting technology a big part of our daily lives.

But how do metal detectors really work that they can be able to sense any objects made up of metal? In this article, we can only focus on consumer metal detectors although the information can also apply to larger metal detectors like the mounted detection systems we usually encounter on airports as well as the handheld security scanners security guards are using.

First we have to know the anatomy of a metal detector. A typical metal detector that is light-weight can compose of only few parts and these are the following:
1. Stabilizer. Although some metal detectors do not have this part, this part is used to keep the unit stable so that when you sweep the head of the metal detector sideways or back and forth the whole equipment remains stable.
2. Control box. This contains the circuitry, batteries, controls, speaker and the microprocessor.
3. Shaft. This serves as the body of the equipment and it connects the control box and the coil so it has a telescopic or adjustable stem that can be set to a more comfortable level for the user.
4. Search coil. This is the loop where actual metal detecting occurs. It is also known as the antenna, loop or search head.
5. Some metal detectors have jack for connecting headphones while other models have small LCD display units on top of the control box but this is optional.

Now this is how metal detecting happens. When you turn the unit on an audible signal occurs. The signal occurs because the current moves through the transmitter coil which create an electromagnetic field in the search coil just like what happens when electricity runs on an electric motor. Since the polarity of the magnetic field is perpendicular to the coil, each time you move the head the current also changes in direction thus the polarity of the magnetic field also changes.

When you move the head of the equipment back and forth, the coil becomes parallel to the ground so the magnetic field that is in the coil will be pushed down into the ground while the objects on the ground which also have magnetic fields pulses back their magnetic fields towards the coil. When there are pulses of pushing and pulling back of magnetic fields, there is the creation of force because of the interaction of the magnetic fields of both the metallic objects that is beneath the coil and the magnetic field that is in the coil. Since the polarity of the objects that is beneath the ground is opposite with the polarity released by the magnetic field of the transmitter’s coil, the magnetic field of the transmitter’s coil will be pushed downward while the object’s magnetic field will be pulsing upward and this creates the signals from the speakers. Since different objects have different magnetic fields, the microprocessor on the equipment sense this so it releases different signals based from how it was programmed on the equipment’s software and this is basically how the system of metal detecting works.

Author Bio: steel bar steel supplier

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