Name: factors that affect electrical resistance
Uploaded: 2023-04-30T12:39:00.000Z
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K12 Standards

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North Carolina K-12 Science Standard Course of Study

9-12

Physical Science

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Motion and Stability- Forces and Interactions

PS.PSc.6.2

Resistance

Wenn ein Strom durch einen Stromkreis fließt, verursachen die Kollisionen zwischen Elektronen und Atomen im Draht einen Widerstand gegen die Bewegung der Elektronen, gemessen in Ohm.
Der elektrische Widerstand einer Schaltung ist das Verhältnis der angelegten Spannung zu dem Strom, der durch sie fließt. Der Widerstand hängt auch vom spezifischen Widerstand des Materials ab und entspricht dem spezifischen Widerstand des Materials multipliziert mit der Länge dividiert durch die Querschnittsfläche des Drahtes.
Die Temperatur beeinflusst den Widerstand von Materialien und kann mit Hilfe der Widerstandsgleichung modelliert werden.
Ein Bauteil in einer Schaltung, das den Stromfluss reduziert, wird als Widerstand bezeichnet, der durch zwei Symbole dargestellt wird, die vom American National Standard Institute und der International Electrotechnical Commission bereitgestellt werden.
Kohlenstoff ist das gebräuchlichste Material, das zur Herstellung von Widerständen verwendet wird. Die Carbon-Leiterbahnen sind um einen Keramikkern gewickelt, der mit zwei Kupferleitungen verbunden und mit vier Bändern zur Kennzeichnung des Widerstands markiert ist.
Die ersten beiden farbigen Bänder stellen die ersten beiden Ziffern des Widerstands dar, während die dritte und vierte Farbe seinen Multiplikator und seine Toleranz darstellen.

<ol>
	<li>OpenStax. (2019). Universitätsphysik Vol. 2. [Web-Version], S. 396–398. Abgerufen von <a href="https://openstax.org/books/university-physics-volume-2/pages/9-3-resistivity-and-resistance">https://openstax.org/books/university-physics-volume-2/pages/9-3-resistivity-and-resistance</a></li>
</ol>

widerstand

Wenn ein Strom durch einen Leiter fließt, verursacht der Leiter einen gewissen Schwierigkeitsgrad für den Stromfluss. Das Maß für diese Schwierigkeit wird als der Widerstand des Materials bezeichnet und wird durch R dargestellt. Jedes Material hat seinen eigenen Widerstand. Im Fall von Leitern wird Wärme abgegeben, wenn ein Strom durch sie fließt. Der Widerstand hängt von der Widerstandsfähigkeit des Materials ab. Die Widerstandsfähigkeit ist eine Eigenschaft des Materials, aus dem elektrische Komponenten hergestellt werden, während der Widerstand eine Eigenschaft der Komponente selbst ist.

Um den Widerstand zu berechnen, betrachte einen Abschnitt eines leitenden Drahtes mit einem Querschnittsbereich von A, einer Länge von L und einer Widerstandsfähigkeit ρ. Eine Batterie ist mit dem Leiter verbunden und erzeugt einen Potentialunterschied von ΔV über ihn. Der Potentialunterschied erzeugt ein elektrisches Feld, das proportional zur Stromdichte ist:

<img alt="Equation1" src="/files/ftp_upload/13747/13747_Equation_1.svg" style="text-align: center; height: 13px;" />

Die Größe des elektrischen Feldes über einem Abschnitt des Leiters ist gleich der Spannung geteilt durch die Länge, und die Größe der Stromdichte ist gleich dem Strom geteilt durch den Querschnittsbereich. Durch das Einsetzen der Werte und die Berücksichtigung, dass das elektrische Feld proportional zur Widerstandsfähigkeit und zur Stromdichte ist, kann eine Beziehung zwischen Spannung und Strom hergestellt werden:

<img alt="Equation2" src="/files/ftp_upload/13747/13747_Equation_2.svg" style="text-align: center; height: 26px;" />

Der Widerstand eines Materials kann als das Verhältnis von Spannung zu Strom definiert werden und wird in Ohm angegeben. Der Widerstand eines zylindrischen Abschnitts eines Leiters ist gleich der Widerstandsfähigkeit des Materials multipliziert mit der Länge geteilt durch den Bereich:

<img alt="Equation3" src="/files/ftp_upload/13747/13747_Equation_3.svg" style="text-align: center; height: 26px;" />

Der Widerstand eines Objekts hängt auch von der Temperatur ab. Für einen gegebenen Zylinder, wenn sich Länge und Bereich nicht stark mit der Temperatur ändern, hat der Widerstand des Materials die gleiche Temperaturabhängigkeit wie die Widerstandsfähigkeit:

<img alt="Equation4" src="/files/ftp_upload/13747/13747_Equation_4.svg" style="text-align: center; height: 13px;" />

wobei R₀ der ursprüngliche Widerstand bei Raumtemperatur, R der Widerstand nach einer Temperaturänderung und α der Temperaturkoeffizient des Materials ist.

Widerstand

Wenn sich ein Strom durch einen Leiter bewegt, verursacht der Leiter eine gewisse Schwierigkeit für den Stromfluss. Das Ausmaß dieser Schwierigkeit ist bekannt ...

Education

Lehre

JoVE Core

Physics

Physik

Unit 1

Einheit 1

Current and Resistance

Strom und Widerstand

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

factors that affect electrical resistance

Electrical resistance describes how much a conductor opposes the flow of current. It is represented by R. When current passes through a conductor, heat is also produced. Resistance is tied to the material’s resistivity, which is a property of the material used to make an electrical component.

Resistance is different from resistivity. Resistivity belongs to the material itself, while resistance belongs to the finished component. To study this relationship, consider a wire with length L, cross-sectional area A, and resistivity ρ. If a battery provides a potential difference ΔV across the wire, the voltage creates an electric field in the conductor.

The electric field across the wire segment equals the voltage divided by the length. The current density equals the current divided by the cross-sectional area. Because the electric field is proportional to resistivity and current density, these values can be combined to relate voltage and current. Resistance is then defined as the ratio of voltage to current and is measured in ohms.

For a cylindrical conductor, resistance equals resistivity multiplied by length divided by area. Resistance also changes with temperature. If the length and area stay nearly the same as temperature changes, the resistance follows the same temperature dependence as the resistivity. In that case, R0 is the original resistance at room temperature, R is the resistance after the temperature change, and α is the temperature coefficient of the material.

Factors That Affect Electrical Resistance

factors-that-affect-electrical-resistance

electrical current

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resistance

Electrical resistance describes how much a conductor opposes the flow of current. It is represented by R. When current passes through a conductor, heat is also produced. Resistance is tied to the material’s resistivity, which is a property of the material used to make an electrical component. Resistance is different from resistivity. Resistivity belongs to the material itself, while resistance belongs to the finished component. To study this relationship, consider a wire with length L,...

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theory of metallic conduction

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key terms and concepts

Learn how resistance depends on resistivity, wire length, cross-sectional area, voltage, current, and temperature in conductors and electrical circuits.

Factors That Affect Electrical Resistance | JoVE K12

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Factors That Affect Electrical Resistance

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