In this article we will look at what exactly makes up a metal detector in order for it to do the job that it does. We will also look at the three types of technology that are also associated with metal detectors.
A typical metal detector will be light weight and consist of just a number of parts.
1. Stabilizer – This is an option and is used to keep the metal detector steady as the person using it sweeps it back and forth.
2. Control Box – This is what contains all the circuitry, controls, speaker, batteries and microprocessor for the metal detector.
3. Shaft – This connects the box to the coil and often adjustable so that people can set it at a comfortable level for their height.
4. Search Coil – Probably one of the most important parts of any metal detector as this actually senses if there is metal there. It may in some cases be referred to as the “search head”, “loop” or “antenna” by some people.
However, most systems will also have a jack for connecting headphones to the metal detector and some will have the control box below the shaft and a small display unit above it.
To operate a metal detector is quite simple. All you need do is turn it on, and then move slowly over the area where you wish to search. In most cases you will sweep the coil backwards and forwards over the ground in front of you and when you pass over a target object then the metal detector will make an audible signal. There are more advanced metal detectors available which provide a display that pinpoints the type of metal that you have detected and how deep in the ground it is.
There are three types of technology that are used in metal detectors and these are:-
1. VLF – Very Low Frequency
This is probably the most popular of the detector technology available today and is made up of two distinct coils, the transmitter coil and the receiver coil.
2. PI – Pulse Induction
Unlike the VLF metal detector the PI system may well use a single coil as both the transmitter and receiver or it may have 2 or even 3 coils working together on it.
3. BFO – Beat Frequency Oscillation
This is the most basic way of detecting metal. In a BFO system there are 2 coils of wire, one of which is in the search head and the other smaller coil will be located inside the control box.