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What are the differences between the magnetic circuit and the physical characteristics of the circuit of a strong magnet?

What are the differences between the magnetic circuit and the physical characteristics of the circuit of a strong magnet?

(1) There are good conductive materials in nature, and there are also materials that insulate current. For example, the resistivity of copper is 1.69×10-2Qmm2/m, while the resistivity of rubber is about 10 times that. But until now, no material has been found to insulate the magnetic flux. 99982μ 。 The smallest permeability of bismuth, its permeability is 0. 99982μ. The permeability of air is 1.000038μ . Therefore, air can be regarded as the material with the lowest magnetic permeability. The relative permeability of the best ferromagnetic material is about 10 to the sixth power.
(2) The current is actually the flow of the charged particles in the conductor. Due to the existence of the conductor resistance, the electromotive force does work on the charged particles and consumes energy, and the power loss is converted into heat energy. The magnetic flux does not represent the motion of any particle, nor does it represent the loss of power, so this analogy is unreasonable. The electrical circuit and the magnetic circuit are inseparable from each other, and each has its own physical and physical constraints. loss, so the analogy is lame. Circuits and magnetic circuits are inseparable from each other, and each has its own physical connotation.

The magnetic circuit is looser:

(1) There is no open circuit phenomenon in the circuit in the magnetic circuit, and the magnetic flux is ubiquitous.
(3) The magnetic circuit is almost always nonlinear. The magnetoresistance of ferromagnetic substances is nonlinear, and the air gap magnetoresistance is linear. The concepts of Ohm’s law and magnetoresistance for magnetic circuits enumerated above are only true in the linear range. Therefore, in the actual design, the B-H curve is usually used to find the working point.
(2) Since there is no substance that is absolutely non-magnetic, the magnetic flux is not constrained, only a part of the magnetic flux passes along the specified magnetic circuit, and the rest is scattered in the space around the magnetic circuit, which is the so-called magnetic flux leakage. It is difficult to calculate and measure accurately, but it cannot be ignored.

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