Oersted
From Wikipedia, the free encyclopedia
For other uses, see Oersted (disambiguation).
Oersted (abbreviated as Oe) is the unit of magnetizing field (also known as magnetic field strength) in the CGS electromagnetic system. One oersted equals a mmf of 1 gilbert per centimeter of flux path. One oersted equals 1000/4π, or 79.58 ampere-turns per meter[1].
From the Standard Handbook of Electrical Engineers; "It is that magnetic vector quantity at a point in a magnetic field which measures the ability of electric currents or magnetized bodies to produce magnetic induction at the given point."[1]
<math>H(\mbox{oersteds})=\frac{1.257NI} {l}</math>
- 1.257 is the conversion factor from 4π/10 if <math>I</math> is expressed in amperes, and <math>l</math> is expressed in centimeters.
- Ampere-turns = N x <math>I</math>
- Magnetomotive force (mmf) = 1.257 N <math>I</math>, so H = mmf divided by magnetic path length.
- In SI units, 1 gilbert = 10/ 4π ampere-turns = about 0.7958 ampere-turn.
- In vacuum, magnetizing field of 1 Oe produces magnetic field of 1 gauss.
- The unit was established by the IEC in 1930 [2] in honour of Hans Christian Ørsted, who discovered electromagnetism in 1820.
[edit] References
- ^ a b Fink,Donald (1969). Standard Handbook For Electrical Engineers. McGraw-Hill. ISBN 0-07-020973-1
- ^ http://www.iec.ch/about/history/ IEC history
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