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MAGNETIC UNITS CONVERSION

DEFINITIONS, TABLES, ONLINE  CALCULATORS, AND EQUATIONS

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Magnetic field is one of two components of electromagnetic field. It is a region where forces acting on moving electric charges can be detected. Magnetic fields are created by moving electric charges or variable electric field. This charge movement may be macroscopic (currents in conductors), or microscopic (associated with spin and orbital motion of electrons, resulting in "permanent magnets").
The SI unit for magnetic flux is the weber (Wb). If the magnetic flux changes by 1 Wb over a time of 1s, then a voltage of 1 V is induced in a conductive loop encircling it: 1 Wb = 1 Vs.
The SI unit for magnetic flux density (magnetic induction)  B is tesla (T): 1 T = 1 Wb/m2 = 1 Vs/m2.
Magnetic field with density of 1 T generates one newton of force per ampere of current per meter of conductor.
When the magnetic fields generated by currents pass through some materials they produce magnetization in the direction of the applied field. In ferromagnetics it results in increased total field B. Quantity called magnetic field strength (or magnetizing force) H is a measure of the applied magnetic field from external currents, independent of the material's magnetic response. Quantity called magnetisation M defines the material's response- it is magnetic moment per unit volume of material. Flux density (magnetic induction) B describes the resulting field in the material. In power electronics it is the main magnetic quantity used in calculation of the minimum required cross-sectional area of power transformer cores.
The table below gives magnetic equations in both SI and CGS systems.

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| MAGNETIC FLUX DENSITY UNIT CONVERSION CALCULATOR | | MAGNETIC FIELD STRENGTH UNIT CONVERSION CALCULATOR |

tesla [T]: |
gauss [Gs, G]: |
weber/square meter: |
weber/square centimeter: |
maxwell/square meter: |
maxwell/sq. centimeter: |
line/square centimeter: |
gamma: |

ampere/meter [A/m]: |
oersted [Oe]: |

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| Calculators are courtesy of www.unitconversion.org |

QUANTITY | SYMBOL | SI UNIT | SI EQUATION | CGS UNIT | CGS EQUATION | CONVERSION FACTOR
Magnetic induction | B | tesla (T) | B=µo(H+M) | Gauss (G) | B = H+4πM | 1 T = 104 G

Magnetic field strength

H

ampere/meter
(A/m)

H = NI/lc
( lc - magnetic
path, m)

Oersted (Oe)

H = 0.4πNI/lc
(lc - magnetic
path, cm)

1 A/m =
4π×10-3 Oe

Magnetic flux

Φ

weber (Wb)

Φ = BAc
(Ac - area, m2 )

Maxwell (M)

Φ = BAc
(Ac - area, cm2 )

1 Wb = 108 M

Magnetization

M

ampere/meter (A/m)

M=m/V
(m- total magnetic moment,
V- volume, m3 )

emu/cm3

M=m/V
(m- total magnetic moment,
V- volume, cm3 )

1 A/m = 10-3
emu / cm3

Magnetic permeability
of vacuum

µo

newton/ampere2

µo= 4π×10-7

1

-

4π×10-7

Inductance

L

henry

L=μoμN2Ac/lc
(N- turns, Ac- area, m2,
lc - magnetic  path, m)

henry

L=0.4πμN2Ac/lc×10-8
(N- turns,
Ac-area, cm2,
lc - magnetic  path, cm)

1

Emf (voltage)

V

volt

V=-NdΦ/dt
(N- turns)

volt

V=-10-8×N×dΦ/dt
(N- turns)

1

| © 2006 L.Rozenblat |

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