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

源变换技术能够将一个与电阻串联的电压源转换为等效的与电阻并联的电流源，反之亦然。
在变换过程中，电路中的电阻值保持不变。利用欧姆定律，可以确定电压或电流的值。
电流源的箭头始终指向电压源的正极。
由于理想电压源和电流源的内阻特性，该技术无法应用于它们。
考虑一个包含电压源、电流源和若干电阻器的电路。通过使用电源变换法，可以确定中心电阻器两端的电压降。
首先，对两个电源应用源变换，以得到简化电路。
现在再次将左侧电压源转换为电流源。电路进一步简化为单一电流源结构。
利用电流分流公式，可求得通过电阻的电流。将其代入欧姆定律，即可求得电阻两端的电压降。

源变换

源变换是电路分析中所采用的一项基本技术，这为简化复杂电路提供了宝贵的工具。该技术涉及了用与电阻器并联的电流源代替与电阻器串联的电压源，反之亦然。这里的关键概念是，当原始源被停用（关闭）时，电路末端的等效电阻将会保持不变。 需要注意的是，在进行源变换时，电流源箭头的方向会始终指向电压源的正极。此规定能够使其确保一致性并有助于保持正确的电路方向。 然而，值得一提的是，源变换不适用于理想的电压源，因为它们具有零内阻。相比之下，非理想电压源具有非零内阻，从而使其更适合电源转换。同样的，具有无限内阻的理想电流源不能用有限的电压源来进行替代。 为了能够说明源变换的实际应用，需要对分别连接到非理想电压源（图1）和非理想电流源（图2）的电路进行分析。当串联电阻等于并联电阻，并且电压源两端的电压遵循欧姆定律时，这些非理想源之间将会变得彼此等效。 <img alt="Figure1" src="/files/ftp_upload/15051/15051_PT_Figure_1.svg" style="text-align: center; height: 128px;"> 图1：采用非理想电压源的电路 <img alt="Figure2" src="/files/ftp_upload/15051/15051_PT_Figure_2.svg" style="text-align: center; height: 128px;"> 图2：采用非理想电流源的电路 用等效的非理想电流源替换非理想电压源是不会改变电路内任何元件的电压或电流特性。这证明了源变换在简化电路分析的过程中具有不影响整体电路行为的强大功能。

源变换是电路分析中采用的一种基本技术，为简化复杂电路提供了有力工具。

Education

教育

JoVE Core

Electrical Engineering

电气工程

Unit 1

第一单元

DC Circuit Analysis

直流电路分析

KEY TERMS AND CONCEPTS

关键术语与概念

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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source transformation

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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key terms and concepts

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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