Types
Metal detectors come in several forms. There are hand-held devices and stand-alone units.
Uses
Hand-held units are usually for personal uses like treasure hunting. Larger stand-alone units are used in buildings and airports for security purposes.
How They Work
All metal detectors work on either electrical or magnetic impulses. There are three types of metal detector technology: very low frequency, pulse induction and beat-frequency oscillation.
Locating Metal
Metal detectors have coils. Electricity or an electromagnetic charge is sent through the coils to the ground and back to the coils. Metallic objects interrupt the signal, which results in the unit creating an audible sound.
Treasure Hunting
Hunting for treasure, lost jewelry and other items, is a popular hobby. Hand-held metal detectors with headphones are the best type for this activity.