Lenz lag
Lenz lag innebär att en inducerad spänning i en sluten krets ger upphov till en inducerad ström med sådan riktning att orsaken till induktionen motverkas. Lagen har fått sitt namn efter Heinrich Lenz (1804-1865). En inducerad ström har alltid sådan riktning att orsaken till dess uppkomst motverkas och erbjuder sålunda ett enkelt sätt att bestämma riktningen hos inducerade strömmar.
Ett exempel på detta är Faradays lag,
- ,
vilken innebär att den inducerade spänningen i en ledare i vila är lika med ändringen av det magnetiska flödet med tiden med omvänt tecken. Det negativa tecknet avser att spänningen ger upphov till en ström som motverkar ändringen i magnetiskt flöde.
Källor
- Cheng, David (1989). Field and Wave Electromagnetics (Second edition), s. 309–310. Addison-Wesley Publishing Company, Inc.
Externa länkar
- Virvelströmmar orsakade av magnet och kopparrör.
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Media som används på denna webbplats
19. Ленцово правило - постојан.ogv
Författare/Upphovsman: Andrejdam, Licens: CC BY-SA 4.0
Lenz's law: When electromagnet is switched on, magnetic flux around the ring increases, which causes induction of electric current in the ring. This current creates magnetic field, which opposes to the reason for its existence and that is the rise of the flux. That is the reason why the ring tries to "escape" from that place. When the electromagnet is switched off the process is reversed, but still the ring opposes to the reason for induction of current in itself. Prepared, performed and explained by Prof. Oliver Zajkov at the Physics Institute at the Ss. Cyril and Methodius University of Skopje, Macedonia.
Författare/Upphovsman: Andrejdam, Licens: CC BY-SA 4.0
Lenz's law: When electromagnet is switched on, magnetic flux around the ring increases, which causes induction of electric current in the ring. This current creates magnetic field, which opposes to the reason for its existence and that is the rise of the flux. That is the reason why the ring tries to "escape" from that place. When the electromagnet is switched off the process is reversed, but still the ring opposes to the reason for induction of current in itself. Prepared, performed and explained by Prof. Oliver Zajkov at the Physics Institute at the Ss. Cyril and Methodius University of Skopje, Macedonia.
Electromagnetic induction.svg
Författare/Upphovsman: Qniemiec, Licens: CC BY-SA 3.0
As the magnetic flux through an area changes, it becomes surrounded by a circular electric field generating a current which countervails the particular flux change
Författare/Upphovsman: Qniemiec, Licens: CC BY-SA 3.0
As the magnetic flux through an area changes, it becomes surrounded by a circular electric field generating a current which countervails the particular flux change