The twisting of a ferromagnetic rod through which an electric current is flowing when the rod is placed in a longitudinal magnetic field. It was discovered by the German physicist Gustav Wiedemann in 1858 [1] . The Wiedemann effect is one of the manifestations of magnetostriction in a field formed by the combination of a longitudinal magnetic field and a circular magnetic field that is created by an electric current. If the electric current (or the magnetic field) is alternating, the rod will begin torsional oscillation.
In linear approach angle of rod torsion α does not depend on its cross-section form and is defined only by current density and magnetoelastic properties of the rod:[2]
Magnetostrictive position sensors use the Wiedemann effect to excite an ultrasonic pulse. Typically a small magnet is used to mark a position along a magnetostrictive wire. The magnetic field from a short current pulse in the wire combined with that from the position magnet excites the ultrasonic pulse. The time required for this pulse to travel from the point of excitation to a pickup at the end of the wire gives the position. Reflections from the other end of the wire could lead to disturbances. In order to avoid this the wire is connected to a mechanical damper that end.[3]
^Wiedemann, Gustav (1881), Electrizitat, 3: 519 {{citation}}: Missing or empty |title= (help)
^Malyugin, Dmitry (1991), "On the theory of Wiedemann effects", Journal of Magnetism and Magnetic Materials, 97 (1–3): 193–197, Bibcode:1991JMMM...97..193M, doi:10.1016/0304-8853(91)90180-i
^"How sensors work - magnetostrictive position sensor".
April 12, 2024
wiedemann, effect, twisting, ferromagnetic, through, which, electric, current, flowing, when, placed, longitudinal, magnetic, field, discovered, german, physicist, gustav, wiedemann, 1858, manifestations, magnetostriction, field, formed, combination, longitudi. The twisting of a ferromagnetic rod through which an electric current is flowing when the rod is placed in a longitudinal magnetic field It was discovered by the German physicist Gustav Wiedemann in 1858 1 The Wiedemann effect is one of the manifestations of magnetostriction in a field formed by the combination of a longitudinal magnetic field and a circular magnetic field that is created by an electric current If the electric current or the magnetic field is alternating the rod will begin torsional oscillation In linear approach angle of rod torsion a does not depend on its cross section form and is defined only by current density and magnetoelastic properties of the rod 2 a jh152G displaystyle alpha j frac h 15 2G where j displaystyle j is current density h15 displaystyle h 15 is magnetoelastic parameter proportional to longitudinal magnetic field value G displaystyle G is the shear modulus Applications editMagnetostrictive position sensors use the Wiedemann effect to excite an ultrasonic pulse Typically a small magnet is used to mark a position along a magnetostrictive wire The magnetic field from a short current pulse in the wire combined with that from the position magnet excites the ultrasonic pulse The time required for this pulse to travel from the point of excitation to a pickup at the end of the wire gives the position Reflections from the other end of the wire could lead to disturbances In order to avoid this the wire is connected to a mechanical damper that end 3 See also editMatteucci effect the inverse effect Magnetostriction Magnetomechanical effects for a collection of similar effectsReferences edit Wiedemann Gustav 1881 Electrizitat 3 519 a href Template Citation html title Template Citation citation a Missing or empty title help Malyugin Dmitry 1991 On the theory of Wiedemann effects Journal of Magnetism and Magnetic Materials 97 1 3 193 197 Bibcode 1991JMMM 97 193M doi 10 1016 0304 8853 91 90180 i How sensors work magnetostrictive position sensor Retrieved from https en wikipedia org w index php title Wiedemann effect amp oldid 991390788, wikipedia, wiki, book, books, library,
