DLE-TEST19 : The BARKHAUSEN EFFECT experiment with the Tests Bench DLE-TB v1
created on february 9, 2013 - JLN Labs - last update march 29, 2013
All informations and diagrams are published freely (freeware) and are intended for a private use and a non commercial use.
Toutes les informations et schémas sont publiés gratuitement ( freeware ) et sont destinés à un usage personnel et non commercial
Cliquez ici pour la version FRANCAISE
March 27, 2013 - DLE-TEST19 : Here a new very interesting experiment that I have conducted with my test platform dedicated to the study of the Delayed Lenz Effect (DLE-TB v1.0). This experiment has suggested me some new hypothesis.
I have observed in the previous DLE-TEST18 that to get the maximal acceleration of the magnetic rotor we need to :
This led me to ask myself the following question :
This led me to turn
to the Barkhausen Effect :
"The Barkhausen effect is a name given to the noise in the magnetic output of a ferromagnet when the magnetizing force applied to it is changed. Discovered by German physicist Heinrich Barkhausen in 1919, it is caused by rapid changes of size of magnetic domains (similarly magnetically oriented atoms in ferromagnetic materials).
Barkhausen's work in acoustics and magnetism led to the discovery, which provided evidence that magnetization affects whole domains of a ferromagnetic material, rather than individual atoms alone. The Barkhausen effect is a series of sudden changes in the size and orientation of ferromagnetic domains, or microscopic clusters of aligned atomic magnets (spins), that occurs during a continuous process of magnetization or demagnetization. The Barkhausen effect offered direct evidence for the existence of ferromagnetic domains, which previously had been postulated theoretically. Heinrich Barkhausen discovered that a slow, smooth increase of a magnetic field applied to a piece of ferromagnetic material, such as iron, causes it to become magnetized, not continuously but in minute steps." Source "Wikipedia : The Barkhausen effect".
The hypothesis are the following :
Below, some photos of the experiment. The excitation coil and its controller are not used here. The secundary coil is connected at the input of a high impedancee phone amplifier. This phone amplifier is used to magnify the Barkhausen noise produced by the motion of the magnetic domains in the ferromagnetic core.
This experiment has fully demonstrated that the effect Barkhaussen is present in the ferromagnetic core of the coil. A very characteristic audio noise can be heard when the rotor is rotating slowly by hand, this special noise is also measured with the oscilloscope.
Below the video of this test about the Barkhausen effect with the DLE-TB v1.0
Documents and references
Demonstration of the Barkhausen effect by the MIT
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