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

Une jauge de contrainte, un transducteur qui convertit les contraintes mécaniques en signaux électriques, est souvent utilisée pour mesurer la force.
Le rôle de l'ingénieur consiste à concevoir le circuit du pont de Wheatstone, à avoir des jauges de contrainte dans chaque bras et à identifier l'amplification requise pour la tension de sortie. Ici, on suppose que la force appliquée augmente la résistance de deux jauges de contrainte tandis que la résistance diminue dans les deux autres. De plus, la relation entre la tension de sortie du pont et la variation de résistance est connue.
Cela peut être réalisé en utilisant le théorème de Thévenin.
Connaissant la tension d’entrée, les courants dans les branches supérieure et inférieure sont d’abord déterminés. Ces valeurs sont ensuite substituées dans la loi d'Ohm pour calculer la tension de Thévenin.
La source est supprimée pour calculer la résistance de Thevenin, et la résistance équivalente est déterminée sous une forme simplifiée.
À partir du circuit équivalent Thevenin, la tension de sortie du pont est calculée à l’aide de la règle de division de la tension.
La comparaison de la relation obtenue avec la relation connue permet de déterminer le gain de l’amplificateur nécessaire pour concevoir le circuit pour qu’il fonctionne dans la plage souhaitée.

exemple de conception : pont à jauges de contrainte

L'utilisation de jauges de contrainte comme transducteurs pour convertir les contraintes mécaniques en signaux électriques est une pratique courante dans diverses applications d'ingénierie. Ces jauges de contrainte sont fréquemment intégrées dans les circuits en pont de Wheatstone pour mesurer avec précision des paramètres tels que la force ou la pression. Dans ce contexte, chaque élément du circuit présente une résistance qui subit de subtiles variations lorsqu'il est soumis à des contraintes mécaniques. L'objectif principal est de convertir de minuscules variations d'une petite tension de sortie en une sortie de tension plus perceptible, qui peut être facilement lue à l'aide d'un voltmètre. En tant qu'ingénieur, les responsabilités comprennent la création d'une conception de jauge de contrainte et la détermination de l'amplification nécessaire pour refléter avec précision les changements de résistance. Cela repose sur l'application du théorème de Thévenin, qui établit le lien entre la tension de sortie du circuit en pont et les variations de résistance. La procédure commence par calculer la tension Thevenin, ce qui nécessite la détermination initiale des courants dans les branches supérieure et inférieure du circuit. En conséquence, ces valeurs de courant calculées sont substituées dans la loi d'Ohm pour dériver la tension de Thevenin. Simultanément, la résistance Thevenin est déterminée en supprimant la source de tension dans une configuration simplifiée. Le circuit équivalent Thevenin trouve la tension de sortie du pont grâce à la règle de division de tension. Le résultat critique de cette analyse permet de déterminer avec précision le gain de l'amplificateur requis pour concevoir le circuit afin qu'il fonctionne efficacement dans la plage opérationnelle spécifiée.

Exemple de conception : pont à jauges de contrainte

Une jauge de contrainte, un transducteur qui convertit les contraintes mécaniques en signaux électriques, est souvent utilisée pour mesurer la force.
Le rôle de l'ingénieur consiste à...

Education

Enseignement

JoVE Core

Electrical Engineering

Génie électrique

Unit 1

Unité 1

DC Circuit Analysis

Analyse des circuits CC

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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.

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Wheatstone Bridge Output for Strain Gauge Design

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