Name: load matching in thevenin circuits
Uploaded: 2024-04-11T12:48:31.000Z
Duration: 1 min 16 s
Channel: JoVE

Dans les applications pratiques, un circuit est conçu pour fournir une puissance maximale d’une source à une charge.
Un circuit équivalent Thevenin peut déterminer la puissance maximale qu’un circuit linéaire peut délivrer.
La puissance délivrée est le produit de la résistance de charge et du carré du courant. Elle varie en fonction de l’évolution de la résistance à la charge.
Pour identifier la valeur de résistance de charge qui maximise la puissance, le calcul différentiel est utilisé. En simplifiant cette équation, on obtient la valeur optimale de résistance à la charge.
Cette valeur de résistance est substituée dans la dérivée seconde de la puissance, ce qui donne une valeur négative, confirmant la condition de puissance maximale.
La valeur de résistance obtenue permet de calculer la puissance maximale. Si la résistance de charge ne correspond pas à la résistance du Thevenin, la puissance réelle délivrée s’écartera de ce maximum.
Selon le théorème de transfert de puissance maximum, le transfert de puissance le plus élevé se produit lorsque la résistance de charge correspond à la résistance de Thevenin.
Considérons une batterie de paramètres connus, reliés par deux résistances de valeurs connues. La résistance qui correspond à la résistance interne de la batterie reçoit la puissance maximale.

transfert de puissance maximal

De nombreuses applications pratiques dans les disciplines d'ingénierie, telles que les télécommunications, nécessitent d'optimiser la fourniture d'énergie à une charge connectée. Cette recherche entraîne cependant des pertes internes inhérentes, qui peuvent être égales ou supérieures à la puissance fournie à la charge. Le circuit équivalent de Thevenin est utile pour trouver la puissance maximale qu'un circuit linéaire peut fournir à une charge. On suppose dans ce contexte que la résistance de charge peut être ajustée. En substituant l'ensemble du circuit par son équivalent Thevenin tout en préservant la charge comme le montre la figure 1; <img alt="Figure1" src="/files/ftp_upload/15055/15055_PT_Figure_1.svg" style="text-align: center; height: 140px;"> Figure 1 : Circuit utilisé pour un transfert de puissance maximal  la puissance délivrée à la charge est donnée par <img alt="Equation1" src="/files/ftp_upload/15055/15055_PT_Equation_1.svg" style="text-align: center; height: 40px;">.................(1) Pour un circuit donné, la résistance et la tension équivalentes de Thevenin sont fixes. La variation de la puissance délivrée à la charge avec la résistance de charge est faible pour des valeurs petites ou grandes de résistance de charge mais maximale pour une certaine valeur de résistance de charge comprise entre zéro et l'infini. La puissance maximale se produit lorsque la résistance de charge est égale à la résistance de Thevenin exprimée en <img alt="Equation2" src="/files/ftp_upload/15055/15055_PT_Equation_2.svg" style="text-align: center; height: 14px;">.................(2) C’est ce qu’on appelle le théorème de transfert de puissance maximale. À l’aide des équations 1 et 2, l’expression de la puissance maximale transférée est obtenue et s’exprime sous la forme <img alt="Equation3" src="/files/ftp_upload/15055/15055_PT_Equation_3.svg" style="text-align: center; height: 40px;">..................(3) Cette équation s'applique uniquement lorsque l'équation 2 est valide, sinon la puissance délivrée à la charge est déterminée à l'aide de l'équation. 1.

Transfert de puissance maximal

Dans les applications pratiques, un circuit est conçu pour fournir une puissance maximale d’une source à une charge.
Un circuit équivalent Thevenin permet de déterminer le ...

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Maximum Power Transfer

load matching in thevenin circuits

Load matching in Thevenin circuits helps a source deliver the most power to a connected load. This matters in engineering fields such as telecommunications, where power delivery must be optimized. Even then, internal losses can be significant and may equal or exceed the power sent to the load.

The Thevenin equivalent circuit is a useful way to study this situation. It replaces the full linear circuit with a simpler source and resistance while keeping the load in place. In this setup, the load resistance is assumed to be adjustable, so the power delivered to it can be tested across different values.

For a fixed circuit, the Thevenin equivalent voltage and resistance do not change. The load power changes only a little when the load resistance is very small or very large. It reaches a maximum at one value between zero and infinity.

The maximum power occurs when the load resistance equals the Thevenin resistance. This condition is called the maximum power transfer theorem. Using the load-power equation and this matching rule, the maximum transferred power can be found. If the matching condition is not met, the load power is determined from the general power equation instead.

Load Matching in Thevenin Circuits

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Load matching in Thevenin circuits helps a source deliver the most power to a connected load. This matters in engineering fields such as telecommunications, where power delivery must be optimized. Even then, internal losses can be significant and may equal or exceed the power sent to the load. The Thevenin equivalent circuit is a useful way to study this situation. It replaces the full linear circuit with a simpler source and resistance while keeping the load in place. In this setup, the load...

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Learn how Thevenin equivalent circuits predict maximum power transfer when load resistance matches Thevenin resistance in linear circuits.

Load Matching in Thevenin Circuits | 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.

electrical engineering

Load Matching in Thevenin Circuits

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