Name: circuit source equivalents
Uploaded: 2025-05-22T09:06:14.000Z
Duration: 1 min 15 s
Channel: JoVE

La technique de transformation de source permet de convertir une source de tension en série avec une résistance en une source de courant équivalente en parallèle avec la résistance ou vice versa.
Pendant la transformation, les valeurs des résistances dans le circuit restent les mêmes. À l'aide de la loi d'Ohm, les valeurs de tension ou de courant peuvent être déterminées.
La flèche de la source de courant pointe toujours vers la borne positive de la source de tension.
Cette technique ne peut pas être appliquée à des sources de tension et de courant idéales en raison de leurs caractéristiques de résistance interne.
Considérons un circuit composé d’une source de tension, d’une source de courant et de quelques résistances. En utilisant la transformation de source, la chute de tension aux bornes de la résistance centrale peut être déterminée.
Dans un premier temps, appliquez la transformation de source dans les deux sources pour obtenir le circuit réduit.
Transformez maintenant à nouveau la source de tension gauche en une source de courant. Le circuit est encore simplifié en une configuration de source de courant unique.
En utilisant la formule de division du courant, le courant traversant la résistance est obtenu. En le substituant dans la loi d'Ohm, la chute de tension aux bornes de la résistance est obtenue.

transformation de la source

La transformation de source est une technique fondamentale utilisée dans l'analyse des circuits, offrant un outil précieux pour simplifier les circuits électriques complexes. Cette technique implique le remplacement soit d'une source de tension en série avec une résistance par une source de courant en parallèle avec une résistance, soit vice versa. Le concept clé ici est que lorsque les sources d'origine sont désactivées (éteintes), la résistance équivalente aux bornes d'extrémité du circuit reste la même. Il est essentiel de noter que lors de transformations de source, la direction de la flèche de la source de courant pointe toujours vers la borne positive de la source de tension. Cette convention garantit la cohérence et aide à maintenir une orientation correcte du circuit. Cependant, il convient de mentionner que la transformation de source n’est pas applicable aux sources de tension idéales, car elles possèdent une résistance interne nulle. En revanche, les sources de tension non idéales présentent une résistance interne non nulle, ce qui les rend propices à la transformation de la source. De même, les sources de courant idéales avec une résistance interne infinie ne peuvent pas être remplacées par des sources de tension finies. Pour illustrer l'application pratique de la transformation de source, considérons un circuit connecté individuellement à une source de tension non idéale (Figure 1) et à une source de courant non idéale (Figure 2). Lorsque la résistance série est égale à la résistance parallèle et que la tension aux bornes de la source de tension adhère à la loi d'Ohm, ces sources non idéales deviennent équivalentes les unes aux autres. <img alt="Figure1" src="/files/ftp_upload/15051/15051_PT_Figure_1.svg" style="text-align: center; height: 128px;"> Figure 1 : Circuit avec une source de tension non idéale <img alt="Figure2" src="/files/ftp_upload/15051/15051_PT_Figure_2.svg" style="text-align: center; height: 128px;"> Figure 2 : Circuit avec une source de courant non idéale Le remplacement de la source de tension non idéale par la source de courant non idéale équivalente ne modifie pas les caractéristiques de tension ou de courant d'un élément du circuit. Cela démontre la puissance de la transformation de source pour simplifier l’analyse des circuits sans affecter le comportement global du circuit.

Transformation de la source

La technique de transformation de source permet de convertir une source de tension en série avec une résistance en une source de courant équivalente en parallèle...

Education

Enseignement

JoVE Core

Electrical Engineering

Génie électrique

Unit 1

Unité 1

DC Circuit Analysis

Analyse des circuits CC

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

Source Transformation

circuit source equivalents

Circuit source equivalents make it easier to simplify electrical circuits in circuit analysis. A source transformation replaces a voltage source in series with a resistor by a current source in parallel with a resistor, or it replaces a current source in parallel with a resistor by a voltage source in series with a resistor.

The key idea is that the equivalent resistance at the circuit terminals stays the same when the original sources are turned off. When making the change, the current source arrow must point toward the positive terminal of the voltage source. This keeps the circuit orientation consistent.

Source transformation does not work for ideal voltage sources because they have zero internal resistance. It also does not work for ideal current sources because they have infinite internal resistance. Nonideal voltage sources and nonideal current sources can be transformed because their internal resistance is not zero or infinite.

The transcript shows this idea with a nonideal voltage source and a nonideal current source. When the series resistance matches the parallel resistance, and the voltage across the voltage source follows Ohm's law, the two sources are equivalent. Replacing the nonideal voltage source with the matching nonideal current source does not change the voltage or current in any circuit element.

Circuit Source Equivalents

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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.

electrical engineering

Circuit Source Equivalents

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