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

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BIO.2

BIO.2.D

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

Design Example: Strain Gauge Bridge or Wheatstone Bridge

Un estensimetro, un trasduttore che converte la deformazione meccanica in segnali elettrici, viene spesso utilizzato per misurare la forza.
Il ruolo dell'ingegnere prevede la progettazione del circuito a ponte di Wheatstone, la presenza di estensimetri in ciascun braccio e l'identificazione dell'amplificazione richiesta per la tensione di uscita. In questo caso, si presume che la forza applicata aumenti la resistenza di due estensimetri mentre la resistenza diminuisca negli altri due. Inoltre, è nota la relazione tra la tensione di uscita del ponte e la variazione della resistenza.
Questo può essere ottenuto usando il teorema di Thevenin.
Conoscendo la tensione di ingresso, vengono prima determinate le correnti nei rami superiore e inferiore. Questi valori vengono poi sostituiti nella legge di Ohm per calcolare la tensione di Thevenin.
La sorgente viene rimossa per calcolare la resistenza di Thevenin e la resistenza equivalente viene determinata in forma semplificata.
Dal circuito equivalente di Thevenin, la tensione di uscita del ponte viene calcolata utilizzando la regola della divisione di tensione.
Il confronto della relazione ottenuta con la relazione nota consente di determinare il guadagno dell'amplificatore necessario per progettare il circuito in modo che funzioni all'interno dell'intervallo desiderato.

esempio di progettazione: ponte estensimetrico

L'utilizzo degli estensimetri come trasduttori per convertire la deformazione meccanica in segnali elettrici è una pratica comune in varie applicazioni ingegneristiche. Questi estensimetri sono spesso integrati nei circuiti a ponte di Wheatstone per misurare con precisione parametri quali forza o pressione. In questo contesto, ogni elemento all'interno del circuito presenta una resistenza che subisce sottili variazioni quando sottoposto a sollecitazione meccanica. L'obiettivo principale è convertire minuscole variazioni nell'uscita di tensione di piccole dimensioni in un'uscita di tensione più distinguibile, che può essere comodamente letta utilizzando un voltmetro.

In qualità di ingegnere, le responsabilità includono la creazione di un progetto di estensimetro e la determinazione dell'amplificazione necessaria per riflettere accuratamente i cambiamenti di resistenza. Ciò si basa sull'applicazione del teorema di Thevenin, che stabilisce la connessione tra la tensione di uscita del circuito a ponte e le variazioni di resistenza.

La procedura inizia calcolando la tensione di Thevenin, che richiede la determinazione iniziale delle correnti all'interno sia del ramo superiore che di quello inferiore del circuito. Di conseguenza, questi valori di corrente calcolati vengono sostituiti nella legge di Ohm per ricavare la tensione di Thevenin. Contemporaneamente, la resistenza di Thevenin viene determinata rimuovendo la sorgente di tensione in una configurazione semplificata.

Il circuito equivalente di Thevenin trova la tensione di uscita del ponte attraverso la regola della divisione della tensione. Il risultato critico di questa analisi consente la determinazione precisa del guadagno dell'amplificatore richiesto per progettare il circuito affinché funzioni efficacemente entro l'intervallo operativo specificato.

Esempio di progettazione: Ponte estensimetrico

Un estensimetro, un trasduttore che converte la deformazione meccanica in segnali elettrici, viene spesso utilizzato per misurare la forza.
Il ruolo dell'ingegnere prevede ...

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JoVE Core

Electrical Engineering

Ingegneria elettrica

Unit 1

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DC Circuit Analysis

Analisi dei circuiti in 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...

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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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