How a Metal Detector Works ?
How a metal detector works?
This question is most asked questions by newbie prospectors or even professionals.
Despite most people don’t care about how a metal detector works , but knowing this
may be useful to get best results from purchased metal detectors.
Here in this article we will talk in detail about principle of metal detector work.
Plus what is the components and parts or tools needed to detect metal underground.
We will give basic ideas in a simplified language because detection technology in the metal detectors
is rather complex and we will not go into too much technical details that does not concern the non-expert reader.
Note : by metal detector we mean a typical metal detector that use a search coil for metal detection
we will not go in detail for other types of metal detectors like 3D Ground Scanners or Long range locator devices.
Metal Detector Parts
1 – Stabilizer : This is the part of the metal detector that makes it comfortable to use.
think of it as the armrest of the device. It stabilizes the metal detector as you move it around.
2 – Control Box : The control box is the brains of the device.
It contains the battery, device controls and settings buttons , the microprocessor, display, and speakers.
3 – Shaft : This is the main part of the detector that all of the other parts connect to.
It’s normally with adjustable length for the user’s comfort. during search.
4 – Search Coil : This is the bottom part of the detector that you swing over the ground.
It’s an antenna that contains coils in it that are integral for the device to be able to detect any metallic
object that is buried underground.
How a Metal Detector Works?
Principle of Work : While metal detectors can be complex, the principle behind their function is fairly simple
A metal detector transmit an magnetic field caused by the electric current flowing through its coils
and then analyze a returned magnetic field as it is returned from the the ground as a result of contacting with
a metallic object.
There are two main search technologies used in typical metal detector device including :
1 – Very Low Frequency (VLF)
In VLF metal detector there are two coils in the search head of the metal detector.
One acts as a transmitter, and the other acts as a receiver.
The first one transmits a magnetic field that result by electricity that moves through the coil.
That magnetic field that is being transmitted will cause electricity to flow into metal objects that it comes into contact with.
The second coil, the receiver, identifies the difference in the resulted magnetic field as the
buried metal absorbs it and the electricity begins to flow through it.
When it detect a change, the second coil sends the alert to the control box through the attached cable,
and you hear the signal from the speakers or your headphones.
The weaker the returning magnetic field the weaker the alert sound.
2 – Pulse Induction (PI)
In pulse induction technology there are one coil only to transmit and receive of magnetic signals.
the coil generate in this case a magnetic field by flowing of the electric current and change its direction
many hundreds times in seconds which called pulses which transmitted into ground, and the coil also
receive the reflected signal from any buried metal object , the difference in signal converted into a digital signal
in the control box as an alert sound depending on signal strength and properties.