Magnetska vodljivost: razlika između inačica

Posljednja izmjena od 29. svibanj 2025. u 10:40

Specifična vodljivost je električna vodljivost žice presjeka 1 mm² dužine 1m.

Pojednostavljeni usporedni pregled magnetske permeabilnosti: feromagnetika (μ_f), paramagnetika(μ_p), vakuuma (μ₀) i dijamagnetika (μ_d).

Magnetska vodljivost (oznaka Λ) šipke ili žice, ploštine poprječnoga presjeka S i duljine l, dana je izrazom:

\Lambda =\mu \cdot {\frac {S}{l}}

gdje je: μ - magnetska permeabilnost; recipročna je vrijednost reluktancije (magnetskoga otpora) magnetskoga kruga; mjerna je jedinica henri (H). ^[1]

Magnetska permeabilnost

Datoteka:Vista-xmag.pngPodrobniji članak o temi: Magnetska permeabilnost

Magnetska permeabilnost je elektromagnetna osobina materijala koja pokazuje intenzitet magnetizacije tijela kada su ona izložena vanjskim magnetnom polju. Magnetska permeabilnost se označava grčkim slovom mi (μ). Pojam magnetska permeabilnost osmislio je Oliver Heaviside 1885. U jedinicama SI sustava, permeabilnost se izražava u Henrijima po metru (H/m), ili u Newtonima po Amperu na kvadrat (N/A²) ili Volt · sekunda na Amper · metar {Vs/Am}.

Magnetska permeabilnost vakuuma ili univerzalna magnetska konstanta (znak $\mu _{0}$ ) je prirodna konstanta magnetske permeabilnosti za vakuum, koja iznosi: $\mu _{0}$ = 4π · 10^–7 H/m ^[2] ili $\mu _{0}$ = 12.566370614 · 10^–7 N/A². Jednaka je recipročnoj vrijednosti umnoška dielektrične permitivnosti vakuuma ε₀ i kvadrata brzine svjetlosti c u vakuumu: μ₀ = 1/(ε₀c²). ^[3]

Vrijednosti za neke materijale

Magnetna susceptibilnost i permeabilnost za odabrane materijale
Materijal	Susceptibilnost χ_m (volumetrijski SI)	Permeabilnost μ [H/m]	Relativna permeabilnost μ/μ₀	Magnetsko polje	Frekvencija (max.)
Metglas		1.26 · 10⁰	1 000 000 ^[4]	kod 0.5 T	100 kHz
Željezo (99.95% čisto Fe normalizirano u H)		2.5 · 10^-1	200 000 ^[5]
Nanoperm		1.0 · 10^-1	80 000 ^[6]	kod 0.5 T	10 kHz
Mu-metal		2.5 · 10^-2	20 000 ^[7]	kod 0.002 T
Mu-metal		6.3 · 10^-2	50 000 ^[8]
Kobalt-željezo (trake visoke permeabilnosti)		2.3 · 10^-2	18 000 ^[9]
Permalloy	8 000	1.0 · 10^-2	8 000	kod 0.002 T
Željezo (99.8% čisto)		6.3 · 10^-3	5 000
Električarski čelik		5.0 · 10^-3	4 000	kod 0.002 T
Feritični nehrđajući čelik (normaliziran)		1.26 · 10^-3 - 2.26 · 10^-3	1 000 – 1 800^[10]
Martenzitni nehrđajući čelik (normaliziran)		9.42 · 10^-4 - 1.19 · 10^-3	750 – 950
Ferit (manganski cink)		> 8.0 · 10^-4	640 (ili više)		100 kHz ~ 1 MHz
Ferit (niklov cink)		2.0 · 10^-5 - 8.0 · 10^-4	16 – 640		100 kHz ~ 1 MHz
Ugljični čelik		1.26 · 10^-4	100	kod 0.002 T
Nikal		1.26 · 10^-4 - 7.54 · 10^-4	100 – 600	kod 0.002 T
Martenzitni nehrđajući čelik (kaljen)		5.0 · 10^-5 - 1.2 · 10^-4	40 – 95
Austenitni nehrđajući čelik		1.26 · 10^-6 - 8.8 · 10^-6	1.003–7 ^[11]
Neodimijev magnet		1.32 · 10^-6	1.05 ^[12]
Platina		1.25697 · 10^-6	1.000265
Aluminij	2.22 · 10^-5 ^[13]	1.256665 · 10^-6	1.000022
Drvo		1.25663760 · 10^-6	1.00000043
Zrak		1.25663753 · 10^-6	1.00000037 ^[14]
Beton (suhi)			1 ^[15]
Vakuum	0	4π × 10⁻⁷ (μ₀)	1 (točno, po definiciji)
Vodik	-2.2 · 10^-9 ^[13]	1.2566371 · 10^-6	1.0000000
Teflon		1.2567 · 10^-6 ^[7]	1.0000
Safir	-2.1 · 10^-7	1.2566368 · 10^-6	0.99999976
Bakar	-6.4 · 10^-6 ili -9.2 · 10^-6 ^[13]	1.256629 · 10^-6	0.999994
Voda	-8.0 · 10^-6	1.256627 · 10^-6	0.999992
Bizmut	-1.66 · 10^-4	1.25643 · 10^-6	0.999834
Supravodič	−1	0	0

Izvori

↑ vodljivost, [1] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.
↑ The NIST reference on fundamental physical constants
↑ magnetska permeabilnost vakuuma, [2] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.
↑
• Parametar accessdate nije dopušten u klasi web
↑
• Parametar accessdate nije dopušten u klasi web
↑
• Parametar format nije dopušten u klasi web
• Parametar accessdate nije dopušten u klasi web
↑ ^7,0 ^7,1
• Parametar accessdate nije dopušten u klasi web
↑
• Parametar accessdate nije dopušten u klasi web
↑
• Parametar accessdate nije dopušten u klasi web
↑ Magnetic Properties of Stainless Steels. Carpenter Technology Corporation 0. 2013 0.
↑ Magnetic Properties of Stainless Steel. Stainless Steel Advisory Service 0. 2000 0.
↑ Juha Pyrhönen, Tapani Jokinen, Valéria Hrabovcová (2009) Design of Rotating Electrical Machines. http://books.google.com/?id=_y3LSh1XTJYC&pg=PT232.
↑ ^13,0 ^13,1 ^13,2
• Parametar accessdate nije dopušten u klasi web
↑ B. D. Cullity and C. D. Graham (2008), Introduction to Magnetic Materials, 2nd edition, 568 pp., p.16
↑
• Parametar accessdate nije dopušten u klasi web

[1] vodljivost, [1] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.

[2] The NIST reference on fundamental physical constants

[3] magnetska permeabilnost vakuuma, [2] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.

[4] 
• Parametar accessdate nije dopušten u klasi web

[Iron-5] 
• Parametar accessdate nije dopušten u klasi web

[Nanoperm-6] 
• Parametar format nije dopušten u klasi web
• Parametar accessdate nije dopušten u klasi web

[hyper-7] 7,0 ^7,1
• Parametar accessdate nije dopušten u klasi web

[nickal-8] 
• Parametar accessdate nije dopušten u klasi web

[vacuumschmeltze-9] 
• Parametar accessdate nije dopušten u klasi web

[Carpenter-10] Magnetic Properties of Stainless Steels. Carpenter Technology Corporation 0. 2013 0.

[SSAS-11] Magnetic Properties of Stainless Steel. Stainless Steel Advisory Service 0. 2000 0.

[12] Juha Pyrhönen, Tapani Jokinen, Valéria Hrabovcová (2009) Design of Rotating Electrical Machines. http://books.google.com/?id=_y3LSh1XTJYC&pg=PT232.

[clarke-13] 13,0 ^13,1 ^13,2
• Parametar accessdate nije dopušten u klasi web

[Cullity2008-14] B. D. Cullity and C. D. Graham (2008), Introduction to Magnetic Materials, 2nd edition, 568 pp., p.16

[15] 
• Parametar accessdate nije dopušten u klasi web

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

@@ Redak 1: / Redak 1: @@
-<!--'''Magnetska vodljivost'''-->[[datoteka:Otpor.jpg|mini|desno|250px|Specifična [[vodljivost]] je [[električna vodljivost]] žice presjeka 1 [[Četvorni metar|mm<sup>2</sup>]] dužine 1[[metar|m]].]]
+[[datoteka:Otpor.jpg|mini|desno|250px|Specifična [[vodljivost]] je [[električna vodljivost]] žice presjeka 1 [[Četvorni metar|mm<sup>2</sup>]] dužine 1[[metar|m]].]]
 [[datoteka:Permeability by Zureks.svg|mini|desno|250px|Pojednostavljeni usporedni pregled magnetske permeabilnosti: [[Feromagnetizam|feromagnetika]] (μ<sub>f</sub>), [[Paramagnetizam|paramagnetika]](μ<sub>p</sub>), [[vakuum]]a (μ<sub>0</sub>) i [[Dijamagnetizam|dijamagnetika]] (μ<sub>d</sub>).]]
@@ Redak 31: / Redak 31: @@
 |
 | 1.26 · 10<sup>0</sup>
-| 1 000 000 <ref>{{cite web|url=http://www.metglas.com/products/page5_1_2_6.htm |title="Metglas Magnetic Alloy 2714A", '&#39;Metglas'&#39; |publisher=Metglas.com |date= |accessdate=2011-11-08}}</ref>
+| 1 000 000 <ref>{{Citiranje weba|url=http://www.metglas.com/products/page5_1_2_6.htm |title="Metglas Magnetic Alloy 2714A", '&#39;Metglas'&#39; |publisher=Metglas.com |date= |accessdate=2011-11-08}}</ref>
 | kod 0.5 [[Tesla|T]]
 | 100&nbsp;kHz
@@ Redak 38: / Redak 38: @@
 |
 | 2.5 · 10<sup>-1</sup>
-| 200 000 <ref name="Iron">{{cite web|url=http://hyperphysics.phy-astr.gsu.edu/hbase/tables/magprop.html#c2 |title="Magnetic Properties of Ferromagnetic Materials", '&#39;Iron'&#39; |publisher=C.R Nave Georgia State University |date= |accessdate=2013-12-01}}</ref>
+| 200 000 <ref name="Iron">{{Citiranje weba|url=http://hyperphysics.phy-astr.gsu.edu/hbase/tables/magprop.html#c2 |title="Magnetic Properties of Ferromagnetic Materials", '&#39;Iron'&#39; |publisher=C.R Nave Georgia State University |date= |accessdate=2013-12-01}}</ref>
 |
 |
@@ Redak 45: / Redak 45: @@
 |
 | 1.0 · 10<sup>-1</sup>
-| 80 000 <ref name="Nanoperm">{{cite web|url=http://www.magnetec.de/eng/pdf/werkstoffkennlinien_nano_e.pdf |title="Typical material properties of NANOPERM", '&#39;Magnetec'&#39; |format=PDF |date= |accessdate=2011-11-08}}</ref>
+| 80 000 <ref name="Nanoperm">{{Citiranje weba|url=http://www.magnetec.de/eng/pdf/werkstoffkennlinien_nano_e.pdf |title="Typical material properties of NANOPERM", '&#39;Magnetec'&#39; |format=PDF |date= |accessdate=2011-11-08}}</ref>
 | kod 0.5 T
 | 10&nbsp;kHz
@@ Redak 52: / Redak 52: @@
 |
 | 2.5 · 10<sup>-2</sup>
-| 20 000 <ref name="hyper">{{cite web|url=http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html |title="Relative Permeability", '&#39;Hyperphysics'&#39; |publisher=Hyperphysics.phy-astr.gsu.edu |date= |accessdate=2011-11-08}}</ref>
+| 20 000 <ref name="hyper">{{Citiranje weba|url=http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html |title="Relative Permeability", '&#39;Hyperphysics'&#39; |publisher=Hyperphysics.phy-astr.gsu.edu |date= |accessdate=2011-11-08}}</ref>
 | kod 0.002 T
 |
@@ Redak 59: / Redak 59: @@
 |
 | 6.3 · 10<sup>-2</sup>
-| 50 000 <ref name="nickal">{{cite web|url=http://www.nickel-alloys.net/nickelalloys.html |title=Nickel Alloys-Stainless Steels, Nickel Copper Alloys, Nickel Chromium Alloys, Low Expansion Alloys |publisher=Nickel-alloys.net |date= |accessdate=2011-11-08}}</ref>
+| 50 000 <ref name="nickal">{{Citiranje weba|url=http://www.nickel-alloys.net/nickelalloys.html |title=Nickel Alloys-Stainless Steels, Nickel Copper Alloys, Nickel Chromium Alloys, Low Expansion Alloys |publisher=Nickel-alloys.net |date= |accessdate=2011-11-08}}</ref>
 |
 |
@@ Redak 66: / Redak 66: @@
 |
 | 2.3 · 10<sup>-2</sup>
-| 18 000 <ref name="vacuumschmeltze">{{cite web|url=http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Downloads/HT/2013-03-27_Soft_Magnetic_Cobalt-_Iron_Alloys_final_version.pdf |title="Soft Magnetic Cobalt-Iron Alloys", '&#39;Vacuumschmeltze'&#39; |publisher=www.vacuumschmeltze.com |date= |accessdate=2013-08-03}}</ref>
+| 18 000 <ref name="vacuumschmeltze">{{Citiranje weba|url=http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Downloads/HT/2013-03-27_Soft_Magnetic_Cobalt-_Iron_Alloys_final_version.pdf |title="Soft Magnetic Cobalt-Iron Alloys", '&#39;Vacuumschmeltze'&#39; |publisher=www.vacuumschmeltze.com |date= |accessdate=2013-08-03}}</ref>
 |
 |
@@ Redak 94: / Redak 94: @@
 |
 | 1.26 · 10<sup>-3</sup> - 2.26 · 10<sup>-3</sup>
-| 1 000 – 1 800<ref name="Carpenter">{{cite web|url=http://www.cartech.com/techarticles.aspx?id=1476|title=Magnetic Properties of Stainless Steels|author=Carpenter Technology Corporation|publisher=Carpenter Technology Corporation|year=2013}}</ref>
+| 1 000 – 1 800<ref name="Carpenter">{{Citiranje weba|url=http://www.cartech.com/techarticles.aspx?id=1476|title=Magnetic Properties of Stainless Steels|author=Carpenter Technology Corporation|publisher=Carpenter Technology Corporation|year=2013}}</ref>
 |
 |
@@ Redak 143: / Redak 143: @@
 |
 | 1.26 · 10<sup>-6</sup> - 8.8 · 10<sup>-6</sup>
-| 1.003–7 <ref name="SSAS">{{cite web|url=http://www.bssa.org.uk/cms/File/SSAS2.81-Magnetic%20Properties.pdf|title=Magnetic Properties of Stainless Steel|author=British Stainless Steel Association|publisher=Stainless Steel Advisory Service|year=2000}}</ref>
+| 1.003–7 <ref name="SSAS">{{Citiranje weba|url=http://www.bssa.org.uk/cms/File/SSAS2.81-Magnetic%20Properties.pdf|title=Magnetic Properties of Stainless Steel|author=British Stainless Steel Association|publisher=Stainless Steel Advisory Service|year=2000}}</ref>
 |
 |
@@ Redak 163: / Redak 163: @@
 |-
 |[[Aluminij]]
-| 2.22 · 10<sup>-5</sup> <ref name="clarke">{{cite web|author=Richard A. Clarke |url=http://www.ee.surrey.ac.uk/Workshop/advice/coils/mu/ |title=Clarke, R. '&#39;Magnetic properties of materials'&#39;, surrey.ac.uk |publisher=Ee.surrey.ac.uk |date= |accessdate=2011-11-08}}</ref>
+| 2.22 · 10<sup>-5</sup> <ref name="clarke">{{Citiranje weba|author=Richard A. Clarke |url=http://www.ee.surrey.ac.uk/Workshop/advice/coils/mu/ |title=Clarke, R. '&#39;Magnetic properties of materials'&#39;, surrey.ac.uk |publisher=Ee.surrey.ac.uk |date= |accessdate=2011-11-08}}</ref>
 | 1.256665 · 10<sup>-6</sup>
 | 1.000022
@@ Redak 186: / Redak 186: @@
 |
 |
-| 1 <ref>{{cite web|author=NDT.net |url=http://www.ndt.net/article/ndtce03/papers/v078/v078.htm |title=Determination of dielectric properties of insitu concrete at radar frequencies |publisher=Ndt.net |date= |accessdate=2011-11-08}}</ref>
+| 1 <ref>{{Citiranje weba|author=NDT.net |url=http://www.ndt.net/article/ndtce03/papers/v078/v078.htm |title=Determination of dielectric properties of insitu concrete at radar frequencies |publisher=Ndt.net |date= |accessdate=2011-11-08}}</ref>
 |
 |

Magnetska vodljivost: razlika između inačica

Posljednja izmjena od 29. svibanj 2025. u 10:40

Magnetska permeabilnost

Vrijednosti za neke materijale

Izvori

Navigacijski izbornik

Traži