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A metal detector is an instrument that detects the nearby presence of metal. Metal detectors are useful for finding metal objects on the surface, underground, and under water. A metal detector consists of a control box, an adjustable shaft, and a variable-shaped pickup coil. When the coil nears metal, the control box signals its presence with a ...
Although the actual inventor of the hand-held metal detector is disputed, the hand-held metal detector was made in 1925 and was first patented by Dr. Gerhard Fisher in 1931. A metal detector had been invented some forty years earlier (1881) by Alexander Graham Bell for the sole purpose of locating a lead bullet in President James A. Garfield.
A full-body scanner is a device that detects objects on or inside a person's body for security screening purposes, without physically removing clothes or making physical contact. Unlike metal detectors, full-body scanners can detect non-metal objects, which became an increasing concern after various airliner bombing attempts in the 2000s.
Induction loop. An induction or inductive loop is an electromagnetic communication or detection system which uses a moving magnet or an alternating current to induce an electric current in a nearby wire. Induction loops are used for transmission and reception of communication signals, or for detection of metal objects in metal detectors or ...
The OPENGATE system is a battery-operated walk-through detector that consists of two free-standing pillars that are 6 feet tall. Metal-detecting hand wands were also purchased and can be used in ...
August 7, 2024 at 8:28 AM. Palm Beach County students head back to school on Monday. When they do, every high schooler in the county will walk through a metal detector, and every student of all ...
After the First World War, work began again on the HD-4. Bell's report to the U.S. Navy permitted him to obtain two 350-horsepower (260-kilowatt) engines in July 1919. On September 9, 1919, the HD-4 set a world marine speed record of 70.86 miles per hour (114.04 kilometres per hour), [ 166 ] a record which stood for ten years.
August 21, 2024 at 9:00 AM. Archaeologists Unearth 1,600 Ancient German Coinsbee32 - Getty Images. A resident of a southwest German town working on a construction project unearthed a stash of ...
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