Md.Kausher ahmed Electrical department

Advanced electricity Code-6722

Lesson declared Magnetization

Learning outcomes After finished this lesson student will able to # Say Magnetization. #Draw Magnetization curve. # Explain Magnetization Equation.

Magnetization The magnetization field or M-field can be defined according to the following equation: Where dm is the elementary magnetic moment and dV is the volume element; in other words, the M-field is the distribution of magnetic moments in the region or manifold concerned. This is better illustrated through the following relation:

Continue,,,,,,,,,, where m is an ordinary magnetic moment and the triple integral denotes integration over a volume. This makes the M-field completely analogous to the electric polarisation field, or P- field, used to determine the electric dipole moment p generated by a similar region or manifold with such a polarization

Continue,,,,,,,,,, Where dp is the elementary electric dipole moment.

Fig:Magnetization

Maxwell's equations The behavior of magnetic fields (B, H), electric fields (E, D), charge density (ρ), and current density (J) is described by Maxwell's equations. The role of the magnetization is described below.

Continue,,,,,,,,,, Relations between B, H, and M The magnetization defines the auxiliary magnetic field H as (SI units) (Gaussian units)

Continue,,,,,,,,,, which is convenient for various calculations. The vacuum permeability μ 0 is, by definition, 4π×10 −7 V·s/(A·m). A relation between M and H exists in many materials. In diamagnets and paramagnets, the relation is usually linear:

Continue,,,,,,,,,, where χ m is called the volume magnetic susceptibility. In ferromagnets there is no one-to-one correspondence between M and H because of Magnetic hysteresis.

Magnetization current The magnetization M makes a contribution to the current density J, known as the magnetization current or bound (volumetric) current. and for the bound surface current:

Continue,,,,,,,,,, so that the total current density that enters Maxwell's equations is given by where J f is the electric current density of free charges (also called the free current), the second term is the contribution from the magnetization, and the last term is related to the electric polarization P.

Feedback #What is star connection? #What is Inductors in Series Equation. # What is Inductors in Series connection

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