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The name "magnetic constant" was briefly used by standards organizations in order to avoid use of the terms "permeability" and "vacuum", which have physical meanings. The change of name had been made because μ 0 was a defined value, and was not the result of experimental measurement (see below). In the new SI system, the permeability of vacuum ...
In SI units, permeability is measured in henries per meter (H/m), or equivalently in newtons per ampere squared (N/A 2). The permeability constant μ 0, also known as the magnetic constant or the permeability of free space, is the proportionality between magnetic induction and magnetizing force when forming a magnetic field in a classical vacuum.
Vacuum permittivity, commonly denoted ε 0 (pronounced "epsilon nought" or "epsilon zero"), is the value of the absolute dielectric permittivity of classical vacuum.It may also be referred to as the permittivity of free space, the electric constant, or the distributed capacitance of the vacuum.
Where and are the charges per length in coulomb-meters, and are polarizability in units of C·m 2 ·V −1, represents the vacuum permittivity constant which is 8.85... × 10 −12 farads per meter, represents the relative permittivity of the surrounding material in farads per meter, is the Boltzmann constant, is temperature in units of kelvin ...
Magnetic susceptibility is a dimensionless proportionality constant that indicates the degree of magnetization of a material in response to an applied magnetic field. A related term is magnetizability , the proportion between magnetic moment and magnetic flux density . [ 3 ]
Another common term encountered for both absolute and relative permittivity is the dielectric constant which has been deprecated in physics and engineering [3] as well as in chemistry. [ 4 ] By definition, a perfect vacuum has a relative permittivity of exactly 1 whereas at standard temperature and pressure , air has a relative permittivity of ...
An MVTR result without specifying these conditions is almost meaningless. Certainly no two results should be compared unless the conditions are known. For example, the effect of temperature on the permeability can be as high as 10% per °C, making it possible that MVTR results achieved at 23°C and 37°C can differ by a factor 4.
It is a measure of material permeability variation after demagnetization, given by a formula = (), where , are permeability values, and t 1, t 2 are time from demagnetization; usually determined for t 1 = 10 min, t 2 = 100 min; range from 2×10 −6 to 12×10 −6 for typical MnZn and NiZn ferrites;