Name: wheatstone bridge output for strain gauge design
Uploaded: 2024-04-11T12:48:31.000Z
Duration: 1 min 15 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Biology

BIO.2

BIO.2.D

design-example-strain-gauge-bridge-or-wheatstone-bridge

Design Example: Strain Gauge Bridge or Wheatstone Bridge

Um medidor de tensão, um transdutor que converte a tensão mecânica em sinais elétricos, é frequentemente usado para medir a força.
O papel do engenheiro envolve projetar o circuito da ponte de Wheatstone, ter medidores de tensão em cada braço e identificar a amplificação necessária para a tensão de saída. Aqui, supõe-se que a força aplicada aumenta a resistência de dois extensômetros enquanto a resistência diminui nos outros dois. Além disso, a relação entre a tensão de saída da ponte e a mudança na resistência é conhecida.
Isso pode ser alcançado usando o teorema de Thevenin.
Conhecendo a tensão de entrada, as correntes nos ramos superior e inferior são determinadas primeiro. Esses valores são então substituídos pela lei de Ohm para calcular a tensão de Thevenin.
A fonte é removida para calcular a resistência de Thevenin e a resistência equivalente é determinada de forma simplificada.
A partir do circuito equivalente de Thevenin, a tensão de saída da ponte é calculada usando a regra de divisão de tensão.
A comparação da relação obtida com a relação conhecida permite a determinação do ganho do amplificador necessário para projetar o circuito para funcionar dentro da faixa desejada.

exemplo de projeto: ponte strain gauge

A utilização de extensômetros como transdutores para conversão de deformações mecânicas em sinais elétricos é uma prática comum em diversas aplicações de engenharia. Esses extensômetros são frequentemente integrados aos circuitos da ponte de Wheatstone para medir com precisão parâmetros como força ou pressão. Nesse contexto, cada elemento do circuito apresenta uma resistência que sofre variações sutis quando submetido a esforços mecânicos. O objetivo principal é converter variações minúsculas na saída de pequena tensão em uma saída de tensão mais discernível, que pode ser lida convenientemente usando um voltímetro.

Na qualidade de engenheiro, as responsabilidades incluem a criação de um projeto de extensômetro e a determinação da amplificação necessária para refletir com precisão as mudanças na resistência. Isto se baseia na aplicação do teorema de Thévenin, que estabelece a conexão entre a tensão de saída do circuito em ponte e as variações na resistência.

O procedimento começa calculando a tensão de Thévenin, que requer a determinação inicial das correntes nos ramos superior e inferior do circuito. Como resultado, esses valores de corrente calculados são substituídos na lei de Ohm para derivar a tensão de Thévenin. Simultaneamente, a resistência de Thévenin é determinada removendo a fonte de tensão em uma configuração simplificada.

O circuito equivalente de Thévenin encontra a tensão de saída da ponte através da regra de divisão de tensão. O resultado crítico desta análise permite a determinação precisa do ganho do amplificador necessário para projetar o circuito para operar efetivamente dentro da faixa operacional especificada.

Exemplo de Projeto: Ponte Strain Gauge

Um medidor de tensão, um transdutor que converte a tensão mecânica em sinais elétricos, é frequentemente usado para medir a força.
O papel do engenheiro envolve ...

Education

JoVE Core

Electrical Engineering

Engenharia Elétrica

Unit 1

Unidade 1

DC Circuit Analysis

Análise de Circuitos CC

KEY TERMS AND CONCEPTS

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wheatstone bridge output for strain gauge design

A strain gauge and Wheatstone bridge work together to turn mechanical strain into an electrical signal. In engineering, this setup is often used to measure force or pressure. Each part of the bridge has a resistance that changes slightly when strain is applied.

The main goal is to turn a very small voltage output into a larger, easier-to-read signal. A voltmeter can then measure that output more clearly. To do this, an engineer designs the strain gauge circuit and figures out how much amplification is needed so the resistance change is shown accurately.

The analysis uses Thevenin's theorem, which links the bridge output voltage to changes in resistance. First, the Thevenin voltage is found by calculating the currents in the upper and lower branches of the circuit. Those currents are then used with Ohm's law to determine the voltage.

Next, the Thevenin resistance is found by removing the voltage source and simplifying the circuit. The Thevenin equivalent circuit is then used with the voltage division rule to find the bridge output voltage. This result helps determine the amplifier gain needed for the circuit to work in the correct operating range.

Wheatstone Bridge Output for Strain Gauge Design

wheatstone-bridge-output-for-strain-gauge-design

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design example: strain gauge bridge or wheatstone bridge

A strain gauge and Wheatstone bridge work together to turn mechanical strain into an electrical signal. In engineering, this setup is often used to measure force or pressure. Each part of the bridge has a resistance that changes slightly when strain is applied. The main goal is to turn a very small voltage output into a larger, easier-to-read signal. A voltmeter can then measure that output more clearly. To do this, an engineer designs the strain gauge circuit and figures out how much...

key terms and concepts

Learn how a strain gauge and Wheatstone bridge convert strain into voltage, and how Thevenin's theorem helps find the amplifier gain needed.

Wheatstone Bridge Output for Strain Gauge Design | 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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Wheatstone Bridge Output for Strain Gauge Design

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