How Do Metal Detectors Work?
When you say “metal detectors” you’ll probably get different ideas from different people. As an example, some people see metal detectors as handheld devices that can be used to find buried treasure and other people see them as large pieces of security equipment that scan for dangerous tools. Metal detectors can be used for various purposes and can be used for leisure or professional use.
VLF Metal Detectors
VLF (Very Low Frequency) metal detectors are the most popular types of detectors and they have 2 distinct coils in their construction: transmitter coils and receiver coils. The transmitter coil is the outer coil and electricity is sent through it which determines the frequency. The receiver coil is the inner loop and it is essentially an antenna that picks up frequencies from items in the ground.
PI Metal Detectors
As a less common type of metal detector, PI (Pulse Induction) detectors have a single coil that acts as both the transmitter and the receiver. It sends sort pulses through the coil that makes a magnetic field. This helps to find other items in the ground as it sends an opposite magnetic field within the object, causing it to be picked up by the unit.
BFO Metal Detectors
Also known as Beat-Frequency Oscillator metal detectors there are 2 different coils of wire. One is in the search head and a smaller one is inside of the control box. These coils are connected to the oscillator that makes thousands of pulses every second. This generates radio waves that create audible tones and if it reaches a metal object, it will interfere with the radio waves. This creates an audible change in the tones.
Finding Buried Objects
One of the main purposes of metal detectors is to find buried objects that are generally within a foot or less from the surface. Most metal detectors might be able to find objects between 8 and 12 inches from the surface, though there are some that may search lower. There are many different factors that will determine whether you will be successful at finding buried items including the halo around the object, the makeup of the soil, and the metal that the object is made out of.
Security Metal Detectors
If you have ever been to an airport, government building, or even a concert you’ve seen the metal detectors that are used to make sure that no one is carrying any illicit objects on them. These metal detectors are essential to make sure that the safety and security of each person is maintained during large events. They are specially designed to give operators the ability to either see or hear if there are metal objects on the person in question. If so, the person will be asked to remove the items from their pockets or they will be subjected to a strip search.
Metal detectors are a large part of our society, whether you love searching for treasure or if you want to feel safe at a huge event. They come in many different shapes, sizes, and types.