Name: voltage balance in closed circuit loops
Uploaded: 2024-04-11T12:48:28.000Z
Duration: 1 min 4 s
Channel: JoVE

K12 Standards

Arizona Science Standards

High School

Physical Science

HS+Phy.P4

HS+Phy.P4U1.8

Kirchhoff's Voltage Law

A lei de tensão de Kirchhoff, ou KVL, é baseada no princípio da conservação de energia.
Ele afirma que a soma algébrica de todas as tensões em torno de um caminho fechado ou loop dentro de um circuito é zero.
A direção do loop ao redor do circuito pode ser no sentido horário ou anti-horário e pode começar de qualquer lugar.
Uma vez escolhida a direção do loop, as tensões positivas têm seu terminal negativo encontrado primeiro e as tensões negativas têm seu terminal positivo encontrado primeiro.
Aplicar KVL a cada loop e reorganizar os termos dá sua forma alternativa, que afirma que a soma da queda de tensão é igual à soma das tensões fornecidas.
Por exemplo, considere as luzes da árvore de Natal onde três luzes LED conectadas em série são amarradas juntas.
Se cada luz requer três volts para acender, a tensão necessária para a bateria alimentar essas luzes é determinada pela aplicação de KVL.
A tensão da bateria é igual à soma da queda de tensão nas três luzes.

lei de tensão de kirchhoff

A Lei de Tensão de Kirchhoff (LTK) é outro princípio fundamental na engenharia elétrica, introduzido pelo físico Gustav Robert Kirchhoff. Esta lei está enraizada no princípio da conservação de energia, que afirma que a energia não pode ser criada nem destruída, apenas transferida ou convertida de uma forma para outra.

LTK afirma que a soma algébrica de todas as tensões em torno de um caminho fechado ou circuito dentro de um circuito é zero. Isso significa que a tensão total fornecida em um circuito é igual à queda total de tensão nos componentes desse circuito.

A direção do loop ao redor do circuito pode ser no sentido horário ou anti-horário e pode começar em qualquer ponto. Uma vez escolhida a direção do circuito, as tensões positivas são aquelas onde o terminal negativo é encontrado primeiro, e as tensões negativas são aquelas onde o terminal positivo é encontrado primeiro.

Ao aplicar LTK no sentido horário e reorganizar os termos, existe uma forma alternativa da lei: a soma das quedas de tensão nos componentes de um circuito é igual à soma das tensões fornecidas.

Considere, por exemplo, um sistema de iluminação doméstica onde três luzes LED conectadas em série são ligadas. Cada luz requer três volts para acender. Ao aplicar LTK, podemos determinar a voltagem necessária para a bateria alimentar essas luzes. A voltagem da bateria é igual à soma da queda de voltagem nas três luzes, que é nove volts.

No entanto, para que o LTK seja verdadeira, uma condição crucial deve ser atendida: um circuito não pode conter duas tensões diferentes em paralelo, a menos que sejam iguais. Isso porque, numa ligação paralela, a mesma tensão é aplicada a todos os componentes, e qualquer discrepância violaria a lei da conservação de energia.

Lei de Tensão de Kirchhoff

A lei de tensão de Kirchhoff, ou KVL, é baseada no princípio da conservação de energia.
Ele afirma que a soma algébrica de todas as tensões em torno de um ...

Education

JoVE Core

Electrical Engineering

Engenharia Elétrica

Unit 1

Unidade 1

Basics of Electric Circuits

Fundamentos de Circuitos Elétricos

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

voltage balance in closed circuit loops

Kirchhoff's Voltage Law explains how voltage is balanced in a closed circuit loop. It is a basic rule in electrical engineering and comes from the idea of energy conservation. Energy can change form, but it cannot be created or destroyed.

KVL states that the algebraic sum of all voltages around a closed path, or loop, is zero. In other words, the total voltage supplied in a loop equals the total voltage drop across the components in that loop. A loop can be traced clockwise or anticlockwise, and it can begin at any point.

The direction of the loop matters when you assign signs to voltages. If you meet the negative terminal first, the voltage is positive. If you meet the positive terminal first, the voltage is negative. When KVL is written in the clockwise direction and the terms are rearranged, the law can also be stated as the sum of voltage drops in a loop equals the sum of supplied voltages.

A simple household lighting example shows how KVL works. Three LED lights connected in series, with each light needing three volts, require a nine-volt battery to power them. The battery voltage matches the sum of the voltage drops across the three lights.

KVL also depends on an important circuit condition. A circuit cannot contain two different voltages in parallel unless those voltages are equal. In parallel connections, the same voltage appears across each component. If the voltages were different, the circuit would break the rule of energy conservation.

Voltage Balance in Closed Circuit Loops

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kirchhoff's current law

Kirchhoff's Current Law at Circuit Nodes

Kirchhoff's Current Law explains how current behaves at a circuit node. A node is the point where two or more circuit elements meet. The law says the current entering a node equals the current leaving it. That balance follows the rule of charge conservation, which means electric charge is not lost at the junction. When applying KCL, currents entering the node are treated as positive and currents leaving the node are treated as negative. The currents can be added algebraically at the node, and...

kirchhoff's voltage law

Kirchhoff's Voltage Law explains how voltage is balanced in a closed circuit loop. It is a basic rule in electrical engineering and comes from the idea of energy conservation. Energy can change form, but it cannot be created or destroyed. KVL states that the algebraic sum of all voltages around a closed path, or loop, is zero. In other words, the total voltage supplied in a loop equals the total voltage drop across the components in that loop. A loop can be traced clockwise or anticlockwise,...

voltage dividers

Series Resistors and Voltage Split

Series resistors split voltage across a circuit. In a series setup, resistors are linked one after another. The same current flows through each resistor in the chain. To analyze this behavior, Ohm's law is used to relate voltage, current, and resistance. Kirchhoff's voltage law says the voltages around a series loop add up to the source voltage. That means the current in the circuit equals the source voltage divided by the total resistance in series. The current value can then be used in Ohm's...

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Parallel Resistors and Current Division

Parallel resistors share the same two nodes, so each resistor has the same voltage across it. In this circuit setup, Kirchhoff's current law applies. The source current equals the sum of the currents through each branch. Ohm's law helps find the branch currents from the source voltage and the resistor values. The source current is equal to the source voltage times the sum of the reciprocals of the resistances. This makes it easier to calculate how current divides in the circuit. The current...

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Resistive Touchscreen Voltage Mapping

A resistive touchscreen uses voltage mapping to locate a finger touch on a mobile device. It is built from two metallic layers. The top layer is flexible, and the bottom layer is rigid. A narrow gap separates them, and the high resistance between the layers is an important part of the design. When a user touches the screen, the two layers meet at one point. That contact point is called the touchpoint. The touch lowers the resistance between the layers at that spot and changes the electrical...

key terms and concepts

Learn how Kirchhoff's Voltage Law balances voltage in a closed loop, how to assign signs, and why a series LED example needs a 9-volt battery.

Voltage Balance in Closed Circuit Loops | 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.

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Voltage Balance in Closed Circuit Loops

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