Metal Detecting Information

Metal detectors use electromagnetic currents to search for metals. Metal detecting is used in airports, courthouse, business and prison security, and had been used to find land mines until manufacturers began to make mines out of ceramic and other non-detectable materials. Metal-detecting hobbyists search for coins, gold and jewelry.

History

In 1881, Alexander Graham Bell invented a crude metal detector to hunt for the slug that mortally wounded President James Garfield. Bell's metal detector used electromagnetic induction. Gerhard Fischar invented the portable metal detector in 1925, which was sold commercially in 1931.

Function

Metal detectors use the principle of electromagnetic induction. Metal detectors have inductor coils which generate pulsating magnetic fields. When metal comes in contact with the field, electric currents, or eddy currents, form. These eddy currents have their own magnetic field which generates an opposite current. This opposite current is detected by the metal detector.

Hobby

Metal detecting is a hobby practiced by many people worldwide. Hobbyists can be found on the beach, in fields, and anywhere else coins or valuables may have been lost or buried. Clubs and organizations exist to help new enthusiasts with tips, instruction and advice.

Security

Metal detectors are an important security measure. These devices, which appear as large frames, can be found in airports, government buildings, police stations, prisons and detention centers and in some schools. Handheld wands are also used by individuals to assist in the security process. The main drawback of metal detectors is their inability to detect chemicals, plastic weapons and ceramic weapons.

Landmines

Metal detectors are used to find antitank and antipersonnel landmines. Antitank landmines are large and contain more metal, making them easier to detect. Metal detectors cannot find plastic or ceramic landmines.