HomeElectricalHow Do Metal Detectors Work? | Hand Held Metal Detector Working Principle

How Do Metal Detectors Work? | Hand Held Metal Detector Working Principle

How do Metal Detectors work? Do you know about the hand held metal detector working principle? Isn’t this a question you have been searching for the answer to? Well, there’s nothing to worry about. Today I’ll provide the answer and that too in a fun way. Friends, when you go to a shopping mall or an important place, you must see that the security guards there has a device in their hands. These start beeping if you have any metal such as coins or your bike key.

Yes, friends, I am talking about metal detectors. Using this technology, our military and security guards provide security services all over the world. In fact, metal detectors are a technology that relies on science and electromagnetism. Let’s find out, how do metal detectors work?

Hand held metal detector working principle

Magnetism and Electricity 

How do metal detectors work- Magnetism

Friends, this metal detector of today is not a new technology. Today, we can use it for various security purposes. But its invention was to search for hidden treasures. Anyway, we will now try to find out how this technology works. Friends, electricity, and magnetism are two subjects in physics that are closely related to each other. You can say, two souls in one body.

That is, wherever there is electricity, there will be magnetism and wherever there is magnetism, electricity will be there. Let’s take a closer look.  Now think about where the electricity in your house is coming from. Maybe from a hydroelectric power plant or a coal power plant or from a generator in your house. However, modern countries have nuclear and wind power plants.

So, now the question is,

How exactly is power generated in these power plants?

How do metal detectors work? If we talk about hydroelectric power stations, there are many big dams at the mouth of a river. Again, there is the creation of a huge stream of water to make the mouth of the river smaller with the dams. Now there is the placement of a huge turbine at the mouth of this stream. Due to the force of the strong current, the turbine starts spinning and is fitted with an electric generator that generates electricity by using rotating energy.

Coal Power Plants

How do metal detectors work- Coal Power Plants
Coal Power Plants

In the same manner, coal power plants works. We heat a lot of water by burning coal in a huge stove.  Now the steam from this hot water helps to turn a turbine and the attachment of this turbine is to an electric generator. This generator generates electricity by using rotating energy. 

So in every case, there is the mention of generators. Now the question is how does the generator generate electricity? See Generator is usually a large copper drum, meaning it has a lot of large copper coils inside. There is a magnetic field around the coil of this copper wire. Now when this coil rotates through the magnetic field at high speed, there is the generation of electricity like magic.

Now we use this generated electricity to run various electric appliances, such as washing machines, electric fans, or electric motors. You see, these electric appliances work in the opposite way to the whole electric generator.  When electricity flows through an electric motor, there is the creation of a variable magnetic field in the copper coil inside the motor. A constant magnetic field always pulls it in the opposite direction, causing the motor to start spinning. However, from so much discussion we have come to the conclusion that we can create magnetism using electricity and generate electricity from magnetism. Moreover, we got this theory first by a Scottish physicist named Maxwell.

How do metal detectors work? / hand held metal detector working principle

Different metal detectors work differently, but each has a common science of working. Metal detectors have a wire coil which we know as a transmitter coil. When electricity flows through this coil, it creates a magnetic field around it.

Now when you move this metal detector over a metal object, some changes will take place in the atom located inside the metal object. This means that the magnetic field from the metal detector will change the orbit of the electron in the metal object. Now we know from Maxwell’s theory that if a magnetic field changes the atom of a metal object, there is a generation of electricity here.

In other words, a metal detector injects a small amount of electricity into a metal object.  Maxwell’s theory states that magnetism is created when electricity is transmitted over a piece of metal. That is, when we move a metal detector over a metal object, the magnetism of the metal detector inserts electricity into the metal object, and there is the creation of another magnetism for the electricity to enter. This is the second magnetism.

Airport Security
Airport Security

Now, we can detect this second magnetism by a metal detector. The metal detector has a second wire coil which goes by the name the receiver coil. Furthermore, the connection of it is to a circuit that has a loudspeaker. I have already said that there is a creation of another magnetism in the metal object which detects the coil in the detector. Again, we can generate electricity in that coil. Now, this electricity goes into the loudspeaker and starts to make a beeping beeping sound. As a result, this is how a metal detector detects a metal object by repeatedly using magnetism and electricity.


The use of metal detectors is in almost all security today, not just to find lost coins. This technology is especially in use in any airport, hospital, shopping mall, scientific laboratory, etc.  Moreover, its use is exclusively for any historical research.

I hope you all have got some important information from today’s post about hand held metal detector working principle. I hope the question, how do metal detectors work? and hand held metal detector working principle – won’t bother you anymore. Although the post was not very big, I still hope I was able to give the main ideas. If you like today’s article, be sure to share and let me know in the comments below any questions or requests or your feedback.

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Sarhan Bakshi
Sarhan Bakshi
I am simply a writer out in search of something new. In the process, giving you all a taste of the fruits born from my intellect.

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