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The magnetic detector or Marconi magnetic detector, sometimes called the "Maggie", was an early radio wave detector used in some of the first radio receivers to receive Morse code messages during the wireless telegraphy era around the turn of the 20th century.
Magnetometers can be used as metal detectors: they can detect only magnetic metals, but can detect such metals at a much greater distance than conventional metal detectors, which rely on conductivity. Magnetometers are capable of detecting large objects, such as cars, at over 10 metres (33 ft), while a conventional metal detector's range is ...
Hall effect magnetometers (also called tesla meters or gauss meters) use a Hall probe [23] with a Hall element to measure magnetic fields or inspect materials (such as tubing or pipelines) using the principles of magnetic flux leakage. A Hall probe is a device that uses a calibrated Hall effect sensor to directly measure the strength of a ...
The basic principle is that the magnetic field "leaks" from the steel at areas where there is corrosion or missing metal. To magnetize the steel, a powerful magnet is used. In an MFL (or Magnetic Flux Leakage) tool, a magnetic detector is placed between the poles of the magnet to detect the leakage field. Analysts interpret the chart recording ...
A MEMS magnetic field sensor is a small-scale microelectromechanical systems (MEMS) device for detecting and measuring magnetic fields (magnetometer). Many of these operate by detecting effects of the Lorentz force : a change in voltage or resonant frequency may be measured electronically, or a mechanical displacement may be measured optically.
As the rotor turns, alternately either an iron section of the disk is in the gap between each pair of stator poles, allowing a high magnetic flux to cross the gap, or else a non-magnetic slot is in the stator gap, allowing less magnetic flux to pass. Thus the magnetic flux through the stator varies sinusoidally at a rapid rate.
The poles are dark, and pole edges are bright. Magnetic field viewing film is used to show stationary or (less often) slowly changing magnetic fields ; it shows their location and direction. It is a translucent thin flexible sheet, coated with micro-capsules containing nickel flakes suspended in oil. [ 1 ]
In radio, a detector is a device or circuit that extracts information from a modulated radio frequency current or voltage. The term dates from the first three decades of radio (1888–1918). The term dates from the first three decades of radio (1888–1918).