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

En 1827, un physicien allemand, Georg Simon Ohm, a démontré expérimentalement la loi d'Ohm.
La loi d'Ohm stipule que le courant traversant un matériau est directement proportionnel à la tension aux bornes du dispositif dans des conditions environnantes constantes.
Tout matériau qui obéit à la loi d'Ohm est connu sous le nom de matériau ohmique, tandis que s'il n'obéit pas à la loi d'Ohm, il est connu comme un matériau non ohmique.
Considérons une autre configuration expérimentale pour démontrer la loi d'Ohm, composée d'une résistance, d'une alimentation, d'un interrupteur, d'un voltmètre et d'un ampèremètre. La tension aux bornes de la résistance est mesurée à l’aide d’un voltmètre, tandis que le courant en ligne avec la résistance est mesuré à l’aide d’un ampèremètre.
Lorsque la résistance est connectée à l’alimentation, le courant circule dans le sens des aiguilles d’une montre, et le voltmètre et l’ampèremètre affichent des lectures positives. À l’inverse, lorsque les fils de l’alimentation sont commutés, le courant circule dans le sens inverse des aiguilles d’une montre, ce qui entraîne des lectures négatives.
Un graphique tracé entre les lectures de tension et de courant s’avère linéaire. La pente de la ligne donne la résistance, confirmant que la résistance est un dispositif ohmique.

<ol>
	<li>OpenStax. (2019). Physique universitaire Vol. 2. [Version Web], p. 396 à 398. Récupéré de <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>

loi d'ohm

De nombreux matériaux présentent une relation simple entre les valeurs du courant, de la tension et de la résistance, connue sous le nom de loi d'Ohm. Le courant qui circule à travers la plupart des substances est directement proportionnel à la tension qui leur est appliquée. Le physicien allemand Georg Simon Ohm (1787–1854) a été le premier à démontrer expérimentalement que le courant dans un fil métallique est directement proportionnel à la tension appliquée. Tout matériau, composant ou appareil qui obéit à la loi d'Ohm, où le courant à travers le dispositif est proportionnel à la tension appliquée, est appelé matériau ohmique ou composant ohmique. Tout matériau ou composant qui n'obéit pas à la loi d'Ohm est appelé matériau non ohmique ou composant non ohmique. Dans un article publié en 1827, Georg Ohm a décrit une expérience dans laquelle il a mesuré la tension et le courant à travers divers circuits électriques simples contenant des longueurs de fil différentes. L'expérience a été utilisée pour observer le courant à travers une résistance qui résulte d'une tension appliquée.

Une autre expérience similaire a été utilisée pour observer le courant à travers une résistance qui résulte d'une tension appliquée. Dans ce circuit simple, une résistance est connectée en série avec une batterie. La tension est mesurée à l'aide d'un voltmètre, qui est placé en parallèle avec la résistance. Le courant est mesuré à l'aide d'un ampèremètre et est placé en série avec la résistance. Plusieurs mesures du courant ont été effectuées pour plusieurs tensions différentes. Le courant à travers la résistance et la tension aux bornes de la résistance ont été mesurés, et un graphique a été tracé entre la tension et le courant, montrant une relation approximativement linéaire. La pente de la ligne est la résistance, ou la tension divisée par le courant. Le résultat est devenu connu sous le nom de loi d'Ohm.

Loi d'Ohm

De nombreux matériaux présentent une relation simple entre les valeurs de courant, de tension et de résistance, connue sous le nom de loi d’Ohm. Le courant qui coule...

Education

Enseignement

JoVE Core

Physics

Physique

Unit 1

Unité 1

Current and Resistance

Courant et résistance

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

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

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resistivity

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resistance

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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

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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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Ohio’s Learning Standards and Model Curriculum

Energy And Waves

Electricity

Electricity And Magnetism

DC circuits

Tennessee Academic Standards

High School

Energy

PHYS.PS3.11

PHYS.PS3.12

Virginia  Standards of Learning

HIgh School

PH.8

PH.8.b

Arizona Science Standards

HS+Phy.P4

HS+Phy.P4U1.8

Alabama Course of Study Science

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Measuring Current, Voltage, and Resistance

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