Ampere-turn: Difference between revisions
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| ⚫ | The '''ampere-turn''' (A⋅t) is the [[MKS system of units|MKS]] (metre–kilogram–second) unit of [[magnetomotive force]] (MMF), represented by a [[direct current]] of one [[ampere]] flowing in a single-turn loop |
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| ⚫ | The '''ampere-turn''' (symbol '''A⋅t''') is the [[MKS system of units|MKS]] (metre–kilogram–second) unit of [[magnetomotive force]] (MMF), represented by a [[direct current]] of one [[ampere]] flowing in a single-turn loop.<ref>{{MW|ampere-turn|accessdate=10 November 2021}}</ref> ''Turns'' refers to the [[winding number]] of an electrical conductor composing an [[electromagnetic coil]]. |
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For example, a current of {{val|2|u=A}} flowing through a coil of 10 turns produces an MMF of {{val|20|u=A⋅t}}. |
For example, a current of {{val|2|u=A}} flowing through a coil of 10 turns produces an MMF of {{val|20|u=A⋅t}}. |
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By maintaining the same current and increasing the number of loops or turns of the coil, the strength of the magnetic field increases because each loop or turn of the coil sets up its own magnetic field. The magnetic field unites with the fields of the other loops to produce the field around the entire coil, making the total magnetic field stronger. |
By maintaining the same current and increasing the number of loops or turns of the coil, the strength of the magnetic field increases because each loop or turn of the coil sets up its own magnetic field. The magnetic field unites with the fields of the other loops to produce the field around the entire coil, making the total magnetic field stronger. |
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The ampere-turn corresponds to {{sfrac|4π|10}} [[Gilbert (unit)|gilbert]]s, the corresponding [[CGS]] unit. |
The ampere-turn corresponds to {{sfrac|4π|10}} [[Gilbert (unit)|gilbert]]s, the corresponding [[CGS]] unit. |
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In [[Thomas Edison]]'s laboratory [[Francis Upton]] was the lead mathematician. Trained with [[Helmholtz]] in Germany, he used ''weber'' as the name of the unit of current, modified to ''ampere'' later: |
In [[Thomas Edison]]'s laboratory [[Francis Upton]] was the lead mathematician. Trained with [[Helmholtz]] in Germany, he used ''weber'' as the name of the unit of current, modified to ''ampere'' later: |
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:He discovered that a Weber turn (that is, an ampere turn) was a constant factor, a given number of which always produced the same effect magnetically.<ref>{{cite book |last1=Jehl |first1=Francis |author1-link=Francis Jehl |title=Menlo Park Reminiscences |date=1937 |publisher=[[Edison Institute]] |location=Dearborn, MI |page=314 |edition=2nd |url=https://babel.hathitrust.org/cgi/pt?id=coo.31924003988429&seq=314 |access-date=10 November 2021 |via=[[HathiTrust]] |hdl=2027/coo.31924003988429 |hdl-access=free}}</ref> |
:He discovered that a Weber turn (that is, an ampere turn) was a constant factor, a given number of which always produced the same effect magnetically.<ref>{{cite book |last1=Jehl |first1=Francis |author1-link=Francis Jehl |title=Menlo Park Reminiscences |date=1937 |publisher=[[Edison Institute]] |location=Dearborn, MI |page=314 |edition=2nd |url=https://babel.hathitrust.org/cgi/pt?id=coo.31924003988429&seq=314 |access-date=10 November 2021 |via=[[HathiTrust]] |hdl=2027/coo.31924003988429 |hdl-access=free}}</ref> |
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==See also== |
== See also == |
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*[[Inductance]] |
* [[Inductance]] |
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*[[ |
* [[Solenoid]] |
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*[[Solenoid]] |
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==References== |
== References == |
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{{reflist}} |
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<references/> |
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{{DEFAULTSORT:Ampere-Turn}} |
{{DEFAULTSORT:Ampere-Turn}} |
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Latest revision as of 11:29, 30 July 2024
 | This article needs additional citations for verification. (January 2013) |
The ampere-turn (symbol A⋅t) is the MKS (metre–kilogram–second) unit of magnetomotive force (MMF), represented by a direct current of one ampere flowing in a single-turn loop.[1] Turns refers to the winding number of an electrical conductor composing an electromagnetic coil. For example, a current of 2 A flowing through a coil of 10 turns produces an MMF of 20 A⋅t. The corresponding physical quantity is NI, the product of the number of turns, N, and the current, I; it has been used in industry, specifically, US-based coil-making industries.[citation needed]
By maintaining the same current and increasing the number of loops or turns of the coil, the strength of the magnetic field increases because each loop or turn of the coil sets up its own magnetic field. The magnetic field unites with the fields of the other loops to produce the field around the entire coil, making the total magnetic field stronger.
The strength of the magnetic field is not linearly related to the ampere-turns when a magnetic material is used as a part of the system. Also, the material within the magnet carrying the magnetic flux "saturates" at some point, after which adding more ampere-turns has little effect.
The ampere-turn corresponds to 4π/10 gilberts, the corresponding CGS unit.
In Thomas Edison's laboratory Francis Upton was the lead mathematician. Trained with Helmholtz in Germany, he used weber as the name of the unit of current, modified to ampere later:
- When conducting his investigations, Upton always noted the Weber turns and with his other data had all that was necessary to put the results of his work in proper form.
- He discovered that a Weber turn (that is, an ampere turn) was a constant factor, a given number of which always produced the same effect magnetically.[2]
See also
[edit]References
[edit]- ^ "ampere-turn". Merriam-Webster.com Dictionary. Merriam-Webster.
- ^ Jehl, Francis (1937). Menlo Park Reminiscences (2nd ed.). Dearborn, MI: Edison Institute. p. 314. hdl:2027/coo.31924003988429. Retrieved 10 November 2021 – via HathiTrust.