Zjawisko Seebecka.pdf

Zjawisko Seebecka

złącza znajdują się w różnych temperaturac h [1] [2] .

Odkryte w 1821 roku przez fizyka niemieckiego (pochodzenia estońskiego) Th. J. Seebecka.

Zjawisko to jest wykorzystywane m.in. w termoparze.

W przedstawionym obwodzie A i B są różnymi metalami lub

półprzewodnikami, T1 i T2 to temperatury w miejscach

styku metali. W tym obwodzie powstaje napięc ie

elektryczne określone wzorem:

Powstające napięcie jest rzędu od kilku do kilkudziesięciu mikrowoltów na kelwin (stopień

Celsjusza).

Natura zjawiska Seebecka

Jeśli próbkę nagrzać

nierównomiernie, to – na skutek

różnicy energii i koncentracji

nośników ładunku – zacznie się ich

ukierunkowany ruch. Jeżeli końce

próbki znajdują się w

temperaturze T1<T2, to na końcu

próbki o temperaturze T2 będzie

występowała większa koncentracja

nośników ładunku, będą one

również miały większą energię. W efekcie wystąpi ich dyfuzja w kierunku zimniejszego

końca (T1). Przepływ prądu dyfuzji prowadzi do pojawienia się rozkładu potencjału oraz

wystąpienia prądu unoszenia . W warunkach równowagi obie składowe prądu są sobie

równe i na zewnątrz obserwuje się tylko różnicę potencjałów między punktami o różnej

temperaturze.

Zjawisko Seebecka – zjawisko termoelektryczne polegające na powstawaniu sił y

elektromotorycznej w obwodzie zawierającym dwa metale lub półprzewodniki gdy ich

Gdzie: S A i S B to współczynniki Seebecka charakterystyczne dla wybranych substancji.

Zjawisko Seebecka

Jeżeli nośnikami ładunku są elektrony ( półprzewodnik typu "n"), to zimniejszy koniec próbki

będzie miał w stosunku do cieplejszego potencjał ujemny. Dla półprzewodnika typu "p" –

dodatni.

Współczynniki Seebecka dla metali w temperaturze 300°C

wspóczynniki Seebeck w µV/K.

0,73

11,6

1,05

-3

-2,2

0,5

-4

0,7

0,82

-4,6

-8,5

-1,6

-4

8,9

0,6

-2,5

-6,7

-3,2

-2

1,05

0,56

-0,58

0,6

-0,05

1,42

1,1

-1,3

13,6

-5,2

-8,43

0,1

-3,6

2,9

4,3

-1,4

-4,4

-6,9

0,8

-5,1

1,19

-2,1

0,3

5,1

-4,1

-2,5

-14,3

0,7

-3,8

0,1

0,7

4,4

5,3

-2,6

-0,04

Przypisy

[1] "Encyklopedia fizyki" praca zbiorowa PWN 1973 t. 3

[2] http:/ / www. if. pwr. wroc. pl/ LPF/ opisy/ w2-cieplo. pdf

Zobacz też

• Efekt Peltiera

• Zjawisko Thomsona

Zjawisko Seebecka

Article Sources and Contributors

Zjawisko Seebecka Source : http://pl.wikipedia.org/w/index.php?oldid=16965483 Contributors : Bart, Beno, Buldożer, Ciacho5, Gregul, Laoo, LukKot,

Mpfiz, NH2501, Puchatech K., Qblik, Roo72, SkyMaja, Stan J Klimas, Stepa, Stok, Tasior, Vazel, 6 anonimowe edycje

Zjawisko Seebecka

Źródła, licencje i autorzy grafiki

Image:Seebeck_effect_circuit_2.png Source : http://pl.wikipedia.org/w/index.php?title=Plik:Seebeck_effect_circuit_2.png License : unknown

Contributors : EugeneZelenko, Ilmari Karonen, Ken g6, LoopZilla, Omegatron, Pieter Kuiper

Grafika: Zjawisko Seebecka w polprzewodnikach.png Source :

http://pl.wikipedia.org/w/index.php?title=Plik:Zjawisko_Seebecka_w_polprzewodnikach.png License : GNU Free Documentation License Contributors :

Puchatech K.

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