How Do Metal Detectors Detect Gold?


Do you know what a metal detector is? Is there anything more enjoyable than metal detectors? I guess no because it unfolds many historical treasures that are buried underground. Most people have seen metal detectors in the shopping mall, stations, airport, etc. It can be used for military or security purposes and to find or detect any unusual object like guns, bombs, etc. Many people do not know how it is used to detect metal, gold, etc. So in this article, we will give a brief review of how do metal detectors work.

What is a metal detector?

One of the most important things one should know is how magnetism is related to an electric field. If one ever came across the coil of wire connected to the battery, then one can feel the electromagnetic field. An electric field and magnetism are like a couple. If you find an electric field, you will automatically find the magnetism.

To make you understand better, we can refer to the example of your daily electric appliances that you use. That electricity we get, provided to us by the power plants is usually produced by the generators, which are generally made of copper wires. Thus when the wire rotates, the magnetic field is generated around it, and the electricity automatically generates inside.

In 1860, a Scottish scientist named James Clark Maxwell genuinely solved this problem and applied his mathematical formula. Basically, from that mathematical formula, we get to know that if there is a changing electric current, you will get a changing magnetic field. That is why magnetism and an electric field are interrelated to each other. And it also gives us a brief idea of how does the metal detector works.

How electromagnetism related to metal detectors?

At first, you need to know that all metal detectors have their way of working. However, science works behind each and every metal detector as the metal detector consists of a coil called a transmitter coil. So when an electric current flows through it, it generates the magnetic field around it.

So when it is brought near to some metallic substances, the magnetic field around the coil affects the atoms inside the substance. And thus, it indicates the presence of any metal or gold. Also, Maxwell states that for a changing electric field, there will be a changing magnetic field too. So, in this case, electromagnetism is directly related to metal detectors.

Why are golds detected through a metal detector?

Since we have discussed electromagnetism, it is prevalent that a chemical element like gold, also made up of an atom, will also get affected by the magnetic field. Therefore, if the search coils of the metal detector are brought near towards gold, the electrons inside will start to move and eventually changes their direction. And thus, it automatically generates the beep sound.

How do metal detectors work?

Few people understand that the metal detector work when it buzzes near some metallic substances. But they don’t know why it buzzes when it brought near some metallic substance. At first, the metal detector consists of a battery that activates the transmitter circuit, which helps pass the electricity through the cable to the search coil.

The search coil of metal detectors transmits an electromagnetic field into the ground. The control box contains an electronic sensor that is where the transmit signals are generated. And also, the received signals which are processed get converted into a target response.

The magnetic field that is produced generates an electric current that flows inside the object. This flow of the electric fields creates a magnetic field around the object, and it cuts the receiver coil. And thus, the tone or the sound is generated.

The audio response that comes from a metal detector is assigned with VDI or visual display indicator. Whenever it is brought near to some metallic substance, it beeps. The nearer it gets to the metallic substance starts to beep more as it is designed like that.

Different types of metal detector

As we discussed above, magnetic fields are generated by changing the electric field, producing a frequency. Metal detector with different frequencies gives a good or bad result in searching for the substance you are looking for.

Metal detectors work broadly in the same way, by converting electricity to magnetism and vice versa. There are three types of metal detectors, namely;

  1. VLF or  Very Low Frequency
  2. PI or Pulse induction
  3. FBS or Full Band Spectrum

Metal detectors were broadly are being used all over the world for many purposes. From the entire article discussed above, you will be able to know how it detects materials like gold, metal, and many substances.

About the Author Mike Chua

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