Name: voltage balance in closed circuit loops
Uploaded: 2024-04-11T12:48:28.000Z
Duration: 1 min 4 s
Channel: JoVE

K12 Standards

Arizona Science Standards

High School

Physical Science

HS+Phy.P4

HS+Phy.P4U1.8

Kirchhoff's Voltage Law

La loi de tension de Kirchhoff, ou KVL, est basée sur le principe de conservation de l'énergie.
Il stipule que la somme algébrique de toutes les tensions autour d’un chemin fermé ou d’une boucle à l’intérieur d’un circuit est nulle.
La direction de la boucle autour du circuit peut être dans le sens des aiguilles d’une montre ou dans le sens inverse des aiguilles d’une montre et peut commencer de n’importe où.
Une fois la direction de la boucle choisie, les tensions positives ont leur borne négative rencontrée en premier, et les tensions négatives ont leur borne positive rencontrée en premier.
L’application de KVL à chaque boucle et la réorganisation des termes donnent sa forme alternative, qui stipule que la somme des chutes de tension est égale à la somme des tensions fournies.
Par exemple, considérez les lumières d’arbre de Noël où trois lumières LED connectées en série sont enfilées ensemble.
Si chaque lumière nécessite trois volts pour s’allumer, la tension nécessaire à la batterie pour alimenter ces lumières est déterminée en appliquant KVL.
La tension de la batterie est égale à la somme de la chute de tension aux trois lumières.

loi de tension de kirchhoff

La loi de tension de Kirchhoff (KVL) est un autre principe fondamental du génie électrique, introduit par le physicien Gustav Robert Kirchhoff. Cette loi est ancrée dans le principe de conservation de l’énergie, selon lequel l’énergie ne peut être ni créée ni détruite, mais seulement transférée ou convertie d’une forme à une autre. KVL déclare que la somme algébrique de toutes les tensions autour d’un chemin fermé ou d’une boucle dans un circuit est nulle. Cela signifie que la tension totale fournie dans une boucle est égale à la chute de tension totale aux bornes des composants de cette boucle. La direction de la boucle autour du circuit peut être dans le sens des aiguilles d’une montre ou dans le sens inverse et peut commencer à partir de n’importe quel point. Une fois la direction de la boucle choisie, les tensions positives sont celles où la borne négative est rencontrée en premier, et les tensions négatives sont celles où la borne positive est rencontrée en premier. En appliquant KVL dans le sens des aiguilles d'une montre et en réorganisant les termes, il existe une forme alternative de la loi : la somme des chutes de tension aux bornes des composants dans une boucle est égale à la somme des tensions fournies. Prenons, par exemple, un système d’éclairage domestique dans lequel trois lampes LED connectées en série sont enchaînées. Chaque lumière nécessite trois volts pour s'allumer. En appliquant le KVL, nous pouvons déterminer la tension nécessaire à la batterie pour alimenter ces lumières. La tension de la batterie est égale à la somme de la chute de tension aux bornes des trois lumières, soit neuf volts. Cependant, pour que KVL soit vrai, une condition cruciale doit être remplie : un circuit ne peut contenir deux tensions différentes en parallèle que si elles sont égales. En effet, dans une connexion parallèle, la même tension est appliquée à tous les composants et toute divergence violerait la loi de conservation de l'énergie.

Loi de tension de Kirchhoff

La loi de tension de Kirchhoff, ou KVL, est basée sur le principe de conservation de l'énergie.
Il stipule que la somme algébrique de toutes les tensions autour d’un ...

Education

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Electrical Engineering

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Unit 1

Unité 1

Basics of Electric Circuits

Les bases des circuits électriques

KEY TERMS AND CONCEPTS

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voltage balance in closed circuit loops

Kirchhoff's Voltage Law explains how voltage is balanced in a closed circuit loop. It is a basic rule in electrical engineering and comes from the idea of energy conservation. Energy can change form, but it cannot be created or destroyed.

KVL states that the algebraic sum of all voltages around a closed path, or loop, is zero. In other words, the total voltage supplied in a loop equals the total voltage drop across the components in that loop. A loop can be traced clockwise or anticlockwise, and it can begin at any point.

The direction of the loop matters when you assign signs to voltages. If you meet the negative terminal first, the voltage is positive. If you meet the positive terminal first, the voltage is negative. When KVL is written in the clockwise direction and the terms are rearranged, the law can also be stated as the sum of voltage drops in a loop equals the sum of supplied voltages.

A simple household lighting example shows how KVL works. Three LED lights connected in series, with each light needing three volts, require a nine-volt battery to power them. The battery voltage matches the sum of the voltage drops across the three lights.

KVL also depends on an important circuit condition. A circuit cannot contain two different voltages in parallel unless those voltages are equal. In parallel connections, the same voltage appears across each component. If the voltages were different, the circuit would break the rule of energy conservation.

Voltage Balance in Closed Circuit Loops

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kirchhoff's current law

Kirchhoff's Current Law at Circuit Nodes

Kirchhoff's Current Law explains how current behaves at a circuit node. A node is the point where two or more circuit elements meet. The law says the current entering a node equals the current leaving it. That balance follows the rule of charge conservation, which means electric charge is not lost at the junction. When applying KCL, currents entering the node are treated as positive and currents leaving the node are treated as negative. The currents can be added algebraically at the node, and...

kirchhoff's voltage law

Kirchhoff's Voltage Law explains how voltage is balanced in a closed circuit loop. It is a basic rule in electrical engineering and comes from the idea of energy conservation. Energy can change form, but it cannot be created or destroyed. KVL states that the algebraic sum of all voltages around a closed path, or loop, is zero. In other words, the total voltage supplied in a loop equals the total voltage drop across the components in that loop. A loop can be traced clockwise or anticlockwise,...

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key terms and concepts

Learn how Kirchhoff's Voltage Law balances voltage in a closed loop, how to assign signs, and why a series LED example needs a 9-volt battery.

Voltage Balance in Closed Circuit Loops | JoVE K12

JoVE Core Electrical Engineering offers easy-to-understand animated videos that cover fundamental concepts of electric circuits along with circuit analysis techniques. It incorporates first-order and second-order circuits using operational amplifiers and circuit transformation concepts. The inclusion of practical design examples and real-world applications through scientist-in-action videos adds significant educational value, making complex concepts accessible.

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Voltage Balance in Closed Circuit Loops

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