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

Em aplicações práticas, um circuito é projetado para fornecer potência máxima de uma fonte para uma carga.
Um circuito equivalente de Thevenin pode determinar a potência máxima que um circuito linear pode fornecer.
A potência fornecida é o produto da resistência da carga e do quadrado da corrente. Varia conforme a resistência de carga muda.
Para identificar o valor da resistência de carga que maximiza a potência, o cálculo diferencial é usado. A simplificação desta equação fornece o valor ideal de resistência à carga.
Este valor de resistência é substituído na segunda derivada de potência, resultando em um valor negativo, confirmando a condição de potência máxima.
O valor da resistência obtida permite o cálculo da potência máxima. Se a resistência de carga não corresponder à resistência de Thevenin, a potência real fornecida se desviará desse máximo.
De acordo com o Teorema da Transferência de Potência Máxima, a maior transferência de potência ocorre quando a resistência da carga corresponde à resistência de Thevenin.
Considere uma bateria de parâmetros conhecidos, conectada a dois resistores de valores conhecidos. A resistência que corresponde à resistência interna da bateria recebe a potência máxima.

transferência máxima de potência

Numerosas aplicações práticas dentro das disciplinas de engenharia, como telecomunicações, exigem a otimização do fornecimento de energia a uma carga conectada. No entanto, essa busca, acarreta perdas internas inerentes, que podem igualar ou exceder a potência fornecida à carga. O circuito equivalente de Thévenin é útil para encontrar a potência máxima que um circuito linear pode fornecer a uma carga. Nesse contexto, assume-se que a resistência da carga pode ser ajustada.

Substituindo todo o circuito pelo seu equivalente de Thevenin preservando a carga conforme mostrado na Figura 1,

<img alt="Figure1" src="/files/ftp_upload/15055/15055_PT_Figure_1.svg" style="text-align: center; height: 140px;" />

Figura 1: Circuito usado para transferência máxima de potência

a potência entregue à carga é dada por

<img alt="Equation1" src="/files/ftp_upload/15055/15055_PT_Equation_1.svg" style="text-align: center; height: 40px;" />.................(1)

Para um determinado circuito, a resistência e a tensão equivalentes de Thévenin são fixas. A potência entregue à carga varia pouco para resistências de carga muito baixas ou muito altas, mas é máxima para algum valor de resistência de carga entre zero e infinito. A potência máxima ocorre quando a resistência da carga é igual à resistência de Thévenin expressa como:

<img alt="Equation2" src="/files/ftp_upload/15055/15055_PT_Equation_2.svg" style="text-align: center; height: 14px;" />.................(2)

Isso é conhecido como teorema de transferência de potência máxima. Utilizando as equações 1 e 2, a expressão para potência máxima transferida é obtida e é expressa como:

<img alt="Equation3" src="/files/ftp_upload/15055/15055_PT_Equation_3.svg" style="text-align: center; height: 40px;" />..................(3)

Esta equação se aplica apenas quando a equação 2 é válida; caso contrário, a potência entregue à carga é determinada usando a Eq. 1.

Transferência Máxima de Potência

Em aplicações práticas, um circuito é projetado para fornecer potência máxima de uma fonte para uma carga.
Um circuito equivalente de Thévenin pode determinar o máximo ...

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Electrical Engineering

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Unit 1

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DC Circuit Analysis

Análise de Circuitos CC

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

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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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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