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.
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
