Name: measuring current, voltage, and resistance
Uploaded: 2023-04-30T12:39:07.000Z
Duration: 1 min 21 s
Channel: JoVE

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

Ohm's Law

Im Jahr 1827 wies der deutsche Physiker Georg Simon Ohm das Ohmsche Gesetz experimentell nach.
Das Ohmsche Gesetz besagt, dass der Strom, der durch ein Material fließt, direkt proportional zur Spannung über dem Gerät unter konstanten Umgebungsbedingungen ist.
Jedes Material, das dem Ohmschen Gesetz gehorcht, wird als ohmsches Material bezeichnet, während es als nichtohmisches Material bezeichnet wird, wenn es nicht dem Ohmschen Gesetz gehorcht.
Betrachten Sie einen anderen Versuchsaufbau, um das Ohmsche Gesetz zu demonstrieren, bestehend aus einem Widerstand, einem Netzteil, einem Schalter, einem Voltmeter und einem Amperemeter. Die Spannung am Widerstand wird mit einem Voltmeter gemessen, während der Strom in Linie mit dem Widerstand mit einem Amperemeter gemessen wird.
Wenn der Widerstand an die Stromversorgung angeschlossen ist, fließt der Strom im Uhrzeigersinn, und das Voltmeter und das Amperemeter zeigen positive Messwerte. Umgekehrt fließt beim Schalten der Leitungen des Netzteils der Strom gegen den Uhrzeigersinn, was zu negativen Messwerten führt.
Ein Diagramm, das zwischen den Spannungs- und Strommesswerten dargestellt wird, erweist sich als linear. Die Steigung der Linie gibt den Widerstand an und bestätigt, dass es sich bei dem Widerstand um ein ohmsches Gerät handelt.

<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/9-4-ohms-law">https://openstax.org/books/university-physics-volume-2/pages/9-4-ohms-law</a></li>
</ol>

ohmsches gesetz

Viele Materialien zeigen eine einfache Beziehung zwischen den Werten von Strom, Spannung und Widerstand, die als Ohmsches Gesetz bekannt ist. Der Strom, der durch die meisten Substanzen fließt, ist direkt proportional zur angelegten Spannung. Der deutsche Physiker Georg Simon Ohm (1787-1854) war der Erste, der experimentell nachwies, dass der Strom in einem Metalldraht direkt proportional zur angelegten Spannung ist. Jedes Material, Bauteil oder Gerät, das dem Ohmschen Gesetz gehorcht, bei dem der Strom durch das Bauteil proportional zur angelegten Spannung ist, wird als ohm'sches Material oder ohm'sches Bauteil bezeichnet. Jedes Material oder Bauteil, das dem Ohmschen Gesetz nicht gehorcht, wird als nicht-ohm'sches Material oder nicht-ohm'sches Bauteil bezeichnet. In einem im Jahr 1827 veröffentlichten Artikel beschrieb Georg Ohm ein Experiment, bei dem er die Spannung über und den Strom durch verschiedene einfache elektrische Schaltungen mit verschiedenen Drahtlängen maß. Das Experiment wurde verwendet, um den Strom durch einen Widerstand zu beobachten, der durch eine angelegte Spannung entsteht.

Ein weiteres ähnliches Experiment wurde durchgeführt, um den Strom durch einen Widerstand zu beobachten, der durch eine angelegte Spannung entsteht. In diesem einfachen Stromkreis ist ein Widerstand in Reihe mit einer Batterie geschaltet. Die Spannung wird mit einem Voltmeter gemessen, das parallel zum Widerstand geschaltet ist. Der Strom wird mit einem Amperemeter gemessen und ist in Reihe mit dem Widerstand geschaltet. Es wurden mehrere Messungen des Stroms für verschiedene Spannungen durchgeführt. Der Strom durch den Widerstand und die Spannung über dem Widerstand wurden gemessen und ein Diagramm wurde erstellt, das eine annähernd lineare Beziehung zwischen der Spannung und dem Strom zeigte. Die Steigung der Linie ist der Widerstand, oder die Spannung geteilt durch den Strom. Das Ergebnis wurde als Ohmsches Gesetz bekannt.

Ohmsches Gesetz

Viele Materialien weisen eine einfache Beziehung zwischen den Werten von Strom, Spannung und Widerstand auf, die als Ohmsches Gesetz bekannt ist. Der Strom, der fließt ...

Education

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Unit 1

Einheit 1

Current and Resistance

Strom und Widerstand

KEY TERMS AND CONCEPTS

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measuring current, voltage, and resistance

Ohm's law describes the relationship between current, voltage, and resistance in many materials. In these cases, the current through a substance is directly proportional to the voltage applied to it. The idea was first shown experimentally by German physicist Georg Simon Ohm, who studied current in a metal wire.

A material, component, or device that follows this pattern is called ohmic. An ohmic component has a current that increases in step with voltage. A material or component that does not follow this pattern is called nonohmic.

Ohm's 1827 experiment measured voltage across and current through simple electrical circuits with different wire lengths. The setup used a resistor connected in series with a battery. A voltmeter measured voltage in parallel with the resistor, and an ammeter measured current in series with the resistor.

Several measurements were taken at different voltages. The current through the resistor and the voltage across it were then graphed. The result was an approximately linear relationship. The slope of that line represents resistance, which is voltage divided by current, and this result became known as Ohm's law.

Measuring Current, Voltage, and Resistance

electrical current

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resistivity

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Resistivity describes how much a material opposes electric current. When a voltage is applied to a conductor, an electric field forms. The charges in the conductor feel that force, and a current density develops. In some materials, including metals at a given temperature, the current density is approximately proportional to the electric field. In those cases, current density can be modeled with conductivity, written as sigma. Electrical conductivity is measured in (ohm·m)^−1. It tells how well...

resistance

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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,...

ohm's law

Ohm's law describes the relationship between current, voltage, and resistance in many materials. In these cases, the current through a substance is directly proportional to the voltage applied to it. The idea was first shown experimentally by German physicist Georg Simon Ohm, who studied current in a metal wire. A material, component, or device that follows this pattern is called ohmic. An ohmic component has a current that increases in step with voltage. A material or component that does not...

non-ohmic devices

Diode Current and Reverse Bias

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electrical power

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boundary conditions for current density

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Current density at a boundary changes when two conducting materials have different electrical conductivities. The normal component of current density stays continuous across the interface. The tangential component, which runs along the surface, becomes discontinuous across the boundary. Consider two conducting media with conductivities σ1 and σ2 separated by an interface. At point P1 in medium 1, the steady current density makes an angle α1 with the normal. At point P2 in medium 2, the current...

electrical conductivity

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theory of metallic conduction

Electron Drift in Metallic Conduction

Electron drift in metallic conduction explains how free electrons move through a conductor. A classical model can describe this motion closely, even though quantum mechanics gives the best overall picture. This model is called the theory of metallic conduction. In this theory, Newton's second law is used to find the acceleration of an electron when an electric field is applied. The electron's velocity is then found from that acceleration. The electron travels through a crystal of positive ions...

key terms and concepts

See how Ohm measured current and voltage in a simple circuit, why some materials are ohmic, and how the graph slope reveals resistance.

Measuring Current, Voltage, and Resistance | JoVE K12

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JoVE Core Physics introduces the theory and application of fundamental physics topics, including kinematics, dynamics, fluid mechanics, statics, waves, and acoustics, with concise and easy-to-understand animated videos. Additionally, the scientist-in-action videos demonstrate the application of related concepts in classical and original research experiments performed in today's laboratories worldwide.

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Ohio’s Learning Standards and Model Curriculum

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Waves and Their Applications in Technologies for Information Transfer

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Florida Department of Education

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New York State Science Learning Standards

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Georgia Standards of Excellence

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Ohm’s Law

SP5.

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Measuring Current, Voltage, and Resistance

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