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In most commercial equipment the AC current surge to the degaussing coil is regulated by a simple positive temperature coefficient (PTC) thermistor device, which initially has a low resistance, allowing a high current, but quickly changes to a high resistance, allowing minimal current, due to self-heating of the thermistor. Such devices are ...
Ferrites can be divided into two groups based on their magnetic coercivity, their resistance to being demagnetized: [2] "Hard" ferrites have high coercivity , so are difficult to demagnetize. They are used to make permanent magnets for applications such as refrigerator magnets , loudspeakers , and small electric motors .
The demagnetizing field, also called the stray field (outside the magnet), is the magnetic field (H-field) [1] generated by the magnetization in a magnet.The total magnetic field in a region containing magnets is the sum of the demagnetizing fields of the magnets and the magnetic field due to any free currents or displacement currents.
Drag coefficients in fluids with Reynolds number approximately 10 4 [1] [2] Shapes are depicted with the same projected frontal area. In fluid dynamics, the drag coefficient (commonly denoted as: , or ) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water.
Based on air resistance, for example, the terminal speed of a skydiver in a belly-to-earth (i.e., face down) free fall position is about 55 m/s (180 ft/s). [3] This speed is the asymptotic limiting value of the speed, and the forces acting on the body balance each other more and more closely as the terminal speed is approached. In this example ...
The magnetization is normally done with a high current pulse that reaches a peak current very quickly and instantaneously turns off leaving the part magnetized. To demagnetize a part, the current or magnetic field needed has to be equal to or greater than the current or magnetic field used to magnetize the part.
Key takeaways. Prolonged exposure to magnets can affect the functionality of your credit card. Cards with magnetic strips can also become demagnetized due to dirt, scratches and other damage.
A samarium–cobalt (SmCo) magnet, a type of rare-earth magnet, is a strong permanent magnet made of two basic elements: samarium and cobalt.. They were developed in the early 1960s based on work done by Karl Strnat at Wright-Patterson Air Force Base and Alden Ray at the University of Dayton.