Name: series and parallel impedance rules
Uploaded: 2024-04-11T12:48:49.000Z
Duration: 1 min 21 s
Channel: JoVE

Considérez une guirlande de lumières de Noël, où chaque ampoule représente une impédance. Cette disposition en série des impédances assure un courant uniforme à travers chaque composant.
En appliquant la loi de tension de Kirchhoff, l'impédance équivalente est égale à la somme des impédances individuelles, comme pour les résistances en série.
La tension de la source est répartie proportionnellement entre plusieurs composants en fonction de leurs impédances respectives, en adhérant au principe de division de la tension.
Dans une connexion en série, le dysfonctionnement d’une seule ampoule déclenche un circuit ouvert, perturbant le flux de courant.
Ainsi, les lumières de Noël sont généralement câblées dans une configuration parallèle, garantissant une tension constante à travers chaque composant.
L'application de la loi du courant de Kirchhoff à ce circuit parallèle révèle que l'inverse de l'impédance équivalente est égale à la somme des inverses des impédances individuelles, comme les résistances en parallèle.
Ainsi, l’admission équivalente est donnée par la somme des admissions individuelles.
Le courant de source se divise entre les composants en proportion inverse de leurs impédances, ce qui démontre le principe de division du courant.
Ici, chaque composant établit un chemin indépendant vers la source d’alimentation, permettant un flux de courant isolé.

combinaison d'impédance

Considérons une chaîne de lumières de Noël, chaque ampoule symbolisant un élément d'impédance. Dans cette configuration en série, le flux de courant électrique reste uniforme sur chaque composant. Ce comportement est conforme à la loi de tension de Kirchhoff (KVL), qui affirme que l'impédance totale dans une telle configuration est égale à la somme des impédances individuelles, comme des résistances en série. Il s’ensuit que la tension de la source d’alimentation est répartie proportionnellement entre ces composants, conformément au principe de division de tension. <img alt="Equation1" src="/files/ftp_upload/15569/15569_PT_Equation_1.svg" style="text-align: center; height: 48px;"> Cependant, l'inconvénient de cette connexion en série est évident lorsqu'une seule ampoule tombe en panne, provoquant un circuit ouvert qui interrompt tout le flux de courant. Les lumières de Noël sont généralement disposées dans une configuration parallèle pour assurer une alimentation électrique continue et stable. Cette configuration garantit une tension constante aux bornes de chaque ampoule, conformément à la loi du courant de Kirchhoff (KCL), où l'inverse de l'impédance équivalente équivaut à la somme des réciproques des impédances individuelles, comme pour les résistances en parallèle. Il s'ensuit que l'admission équivalente est la somme des admissions individuelles. Dans cet agencement parallèle, le courant source se divise inversement en fonction des impédances des ampoules individuelles, illustrant le principe de division du courant. Notamment, chaque ampoule établit un chemin indépendant vers la source d’alimentation, permettant un flux de courant isolé et ininterrompu. <img alt="Equation2" src="/files/ftp_upload/15569/15569_PT_Equation_2.svg" style="text-align: center; height: 48px;"> <img alt="Equation3" src="/files/ftp_upload/15569/15569_PT_Equation_3.svg" style="text-align: center; height: 40px;"> De plus, dans les circuits plus complexes avec des impédances série et parallèle, les transformations delta en étoile et étoile en triangle peuvent également être utilisées pour les circuits d'impédance, offrant ainsi de précieux outils d'analyse et de conception de circuits. Ces transformations facilitent la conversion entre différentes configurations d'impédance, améliorant ainsi la polyvalence des circuits basés sur l'impédance.

Combinaison d'impédance

Considérez une guirlande de lumières de Noël, où chaque ampoule représente une impédance. Cette disposition en série des impédances assure un courant uniforme à travers ...

Education

Enseignement

JoVE Core

Electrical Engineering

Génie électrique

Unit 1

Unité 1

AC Circuit Analysis

Analyse des circuits CA

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

Impedance Combination

series and parallel impedance rules

Impedance in series and parallel circuits follows the same rules used for resistors. A string of Christmas lights is a simple example. Each bulb represents one impedance element. In a series connection, the current stays the same through every component.

This series behavior matches Kirchhoff’s Voltage Law, or KVL. The total impedance in the circuit is the sum of the individual impedances. The source voltage is then divided among the components based on their values. This is the voltage division principle. One weak point of a series circuit is that one failed bulb can open the circuit and stop current flow.

Christmas lights are often wired in parallel to avoid that problem. In a parallel circuit, each bulb keeps its own path to the power source. The voltage across each bulb stays constant. This matches Kirchhoff’s Current Law, or KCL. For parallel impedance, the reciprocal of the equivalent impedance equals the sum of the reciprocals of the individual impedances.

The equivalent admittance is the sum of the individual admittances. Admittance is the inverse of impedance. In this setup, the source current splits according to the impedances of the branches. This is the current division principle. Because each bulb has an independent path, current can keep flowing even if one branch fails.

For circuits that mix series and parallel impedances, delta-to-wye and wye-to-delta transformations are useful. These methods let students convert one impedance network into another form. They make circuit analysis and design more flexible.

Series and Parallel Impedance Rules

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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

Series and Parallel Impedance Rules

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