Oersted
oersted | |
---|---|
magnetic field strength | |
Symbol | Oe |
Named after | Hans Christian Ørsted |
Derivation | 1 dyn/Mx |
Conversions | |
1 Oe in ... | ... is equal to ... |
Gaussian base units | 1 cm−1/2⋅g1/2⋅s−1 |
SI units | (4π)−1×103 A/m ≈ 79.57747 A/m |
The oersted (
Difference between CGS and SI systems
In the CGS system, the unit of the
History
The unit was established by the IEC in the 1930s [4] in honour of Danish physicist Hans Christian Ørsted. Ørsted discovered the connection between magnetism and electric current when a magnetic field produced by a current-carrying copper bar deflected a magnetised needle during a lecture demonstration.[5]
Definition
The oersted is defined as a
The H-field strength inside a long solenoid wound with 79.58 turns per meter of a wire carrying 1 A is approximately 1 oersted. The preceding statement is exactly correct if the solenoid considered is infinite in length with the current evenly distributed over its surface.
The oersted is closely related to the gauss (G), the CGS unit of magnetic flux density. In a vacuum, if the magnetizing field strength is 1 Oe, then the magnetic field density is 1 G, whereas, in a medium having
Because oersteds are used to measure magnetizing field strength, they are also related to the magnetomotive force (mmf) of current in a single-winding wire-loop:
Stored energy
The stored energy in a magnet, called magnet performance or maximum energy product[12] (often abbreviated BHmax), is typically measured in units of megagauss-oersteds (MG⋅Oe).
See also
- Centimetre–gram–second system of units
- Ampere's model of magnetization
References
- ^ "Oersted". Random House Webster's Unabridged Dictionary.
- ISBN 978-8885259003, pp. 53–56
- ^ Kaye, G. W. C, & Laby, T. H.: Table of Physical and Chemical Constants, page 14. Longman, 1973.
- ^ "IEC history". Archived from the original on 2019-05-21. Retrieved 2006-03-25.
- ^ "Hans Christian Oersted - Biography, Facts and Pictures". Retrieved 2020-03-31.
- ^ Hirst, A. W. Electricity and Magnetism For Engineering Students. Blackie & Son Limited, 1959, p.411
- ^ Magnetic Conversion Factors
- ^ EMF Fundamentals Archived 2008-04-07 at the Wayback Machine
- ^ Everything2.com • Oersted
- ^ Derived CGS Units with Special Names
- . SI Brochure: The International System of Units (SI) [8th edition, 2006; updated in 2014].
- ^ "What is Maximum Energy Product / BHmax and How Does It Correspond to Magnet Grade? | Dura Magnetics USA". Retrieved 2020-01-20.