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

A técnica de transformação de fonte permite a conversão de uma fonte de tensão em série com um resistor em uma fonte de corrente equivalente em paralelo com o resistor ou vice-versa.
Durante a transformação, os valores do resistor no circuito permanecem os mesmos. Usando a lei de Ohm, os valores de tensão ou corrente podem ser determinados.
A seta da fonte de corrente sempre aponta para o terminal positivo da fonte de tensão.
Esta técnica não pode ser aplicada a fontes ideais de tensão e corrente devido às suas características de resistência interna.
Considere um circuito que consiste em uma fonte de tensão, uma fonte de corrente e alguns resistores. Usando a transformação da fonte, a queda de tensão no resistor central pode ser determinada.
Inicialmente, aplique a transformação de origem em ambas as fontes para obter o circuito reduzido.
Agora transforme a fonte de tensão esquerda novamente em uma fonte de corrente. O circuito é ainda mais simplificado em uma única configuração de fonte de corrente.
Usando a fórmula de divisão de corrente, a corrente através do resistor é obtida. Ao substituí-lo na lei de Ohm, a queda de tensão no resistor é obtida.

transformação da fonte

A transformação de fontes é uma técnica fundamental empregada na análise de circuitos, oferecendo uma ferramenta valiosa para simplificar circuitos elétricos complexos. Essa técnica envolve a substituição de uma fonte de tensão em série com um resistor por uma fonte de corrente em paralelo com um resistor, ou vice-versa. O conceito chave aqui é que quando as fontes originais são desativadas (desligadas), a resistência equivalente nos terminais finais do circuito permanece a mesma.

É essencial observar que ao realizar transformações de fonte, a direção da seta da fonte de corrente sempre aponta para o terminal positivo da fonte de tensão. Esta convenção garante consistência e ajuda a manter a orientação adequada do circuito.

Porém, vale ressaltar que a transformação de fontes não é aplicável a fontes de tensão ideais, pois possuem resistência interna zero. Em contraste, as fontes de tensão não ideais apresentam resistência interna diferente de zero, tornando-as passíveis de transformação de fonte. Da mesma forma, fontes de corrente ideais com resistência interna infinita não podem ser substituídas por fontes de tensão finitas.

Para ilustrar a aplicação prática da transformação de fonte, considere um circuito conectado a uma fonte de tensão não ideal (Figura 1) e a uma fonte de corrente não ideal (Figura 2) individualmente. Quando a resistência em série é igual à resistência em paralelo e a tensão na fonte de tensão segue a lei de Ohm, essas fontes não ideais tornam-se equivalentes entre si.

<img alt="Figure1" src="/files/ftp_upload/15051/15051_PT_Figure_1.svg" style="text-align: center; height: 128px;" />

Figura 1: Circuito com fonte de tensão não ideal  

<img alt="Figure2" src="/files/ftp_upload/15051/15051_PT_Figure_2.svg" style="text-align: center; height: 128px;" />

Figura 2: Circuito com fonte de corrente não ideal

A substituição da fonte de tensão não ideal pela fonte de corrente não ideal equivalente não altera as características de tensão ou corrente de qualquer elemento do circuito. Isso demonstra o poder da transformação da fonte na simplificação da análise do circuito sem afetar o comportamento geral do circuito.

Transformação da Fonte

A técnica de transformação de fonte permite a conversão de uma fonte de tensão em série com um resistor em uma fonte de corrente equivalente em paralelo ...

Education

JoVE Core

Electrical Engineering

Engenharia Elétrica

Unit 1

Unidade 1

DC Circuit Analysis

Análise de Circuitos CC

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

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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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...

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Learn how source transformation replaces nonideal voltage and current sources while keeping terminal resistance the same in circuit analysis.

Circuit Source Equivalents | 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

Circuit Source Equivalents

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