How a Metal Detector Works
The metal detector, as the name suggests, is a tool to detect the presence of metal. The most often used places for metal detectors are the airports for check ins and high security areas.
If you are carrying a metallic object, the job of metal detector is to detect it. Even when the metallic objects are lying on the ground, metal detectors can detect them too. Metal detectors can see through non-metallic surfaces. No wonder, it can see inside your bag, and detect the metallic piece instantly. Metal detectors don’t only find applications in security areas, but are abundantly used in treasure hunting as well and for finding lost items that consist of metal. This wonderful application of science was invented by none other than the legendary Alexander Graham Bell more than 125 years back in the year 1881. Fischer came out with a portable metal detector in 1931.
There have been many more modifications in the first portable detector made by Fischer. Hans Oersted was responsible for discovering electromagnetism. Electromagnetism is the science of studying two forces: those of electricity and magnetic in tandem with each other.
Metal detectors are supposed to be very good conductors of electricity and magnetism. Therefore it is quite natural that the metal detector is affected by electromagnetism in the surrounding.
A high powered coil generates magnetic effect with the help of power generated by the attached battery. When this electromagnetic field penetrates the ground, the metals tend to get charted with magnetism.
The coil detects the electromagnetic behavior and a signal is sent to the electronic box. The speaker attached to the electronic box beeps and alerts the operator immediately of the presence of metal.
Modern metal detectors work on the similar principle with more electronics added. Now you’ll find microprocessors can indicate the presence of a metal type. It can measure the time between charging of metal and the receiving of the beep that concludes the type of metal and this length of time is known as phase shift.
There are adjustments in the device when searching for a particular kind of metal. Some detectors can even tell you on a view screen what it is that they found.
Metal detectors have electronic boxes with a battery case on one end and a handle for the operative’s arm on the other. It has a coil made of insulated wire wound around a telescoping shaft that is inside a plastic disk. The device is held parallel to the ground due to the angle at which the disk comes out of the shaft. The electronic box is held in the band, the power is put on and the coil end is slowly swept over the ground.
If the trace of metal is there on or buried in the ground, an electronic beep is heard when the device sweeps the ground.
Working with a metal detector is easy. With just a few hours of training a person can become very good at properly using a metal detector.
Now with the war against terrorism going on around Pakistan and so many suicide bombers exploding themselves in the country with continuously deteriorating the low and order situation, more and more entrepreneurs are using metal detectors to safeguard their installations. Its use also arises a little chaos at times as it make buzz on sensing the metal used in even one’s fly, button, shoes, hair clips, artificial jewelry or cufflink.