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

A strain gauge, a transducer that converts mechanical strain into electrical signals, is often used to measure force.
The engineer&#39;s role involves designing the Wheatstone bridge circuit, having strain gauges in each arm, and identifying the required amplification for the output voltage. Here, it is assumed that the applied force increases the resistance of two strain gauges while the resistance decreases in the other two. Also, the relationship between the bridge output voltage and the change in resistance is known.
This can be achieved using Thevenin&#39;s theorem.
Knowing the input voltage, the currents in the top and bottom branches are first determined. These values are then substituted into Ohm&#39;s law to calculate the Thevenin voltage.
The source is removed to calculate the Thevenin resistance, and the equivalent resistance is determined in a simplified form.
From the Thevenin equivalent circuit, the bridge output voltage is calculated using the voltage division rule.
Comparing the obtained relation with the known relation allows the determination of the amplifier gain needed to design the circuit to work within the desired range.

design example: strain gauge bridge or wheatstone bridge

The utilization of strain gauges as transducers for converting mechanical strain into electrical signals is a common practice in various engineering applications. These strain gauges are frequently integrated into Wheatstone bridge circuits to accurately measure parameters such as force or pressure. Within this context, each element within the circuit exhibits a resistance that undergoes subtle variations when subjected to mechanical strain. The primary objective is to convert minuscule variations in small voltage output into a more discernible voltage output, which can be conveniently read using a voltmeter.
In the engineer&#39;s capacity, the responsibilities include creating a strain gauge design and determining the necessary amplification to reflect changes in resistance accurately. This relies upon the application of Thevenin&#39;s theorem, which establishes the connection between the output voltage of the bridge circuit and variations in resistance.
The procedure starts by calculating the Thevenin voltage, which requires the initial determination of currents within both the upper and lower branches of the circuit. As a result, these computed current values are substituted into Ohm&#39;s law to derive the Thevenin voltage. Simultaneously, Thevenin resistance is determined by removing the voltage source in a simplified configuration.
The Thevenin equivalent circuit finds the bridge&#39;s output voltage through the voltage division rule. The critical outcome of this analysis enables the precise determination of the amplifier gain required for designing the circuit to operate effectively within the specified operational range.

A strain gauge, a transducer that converts mechanical strain into electrical signals, is often used to measure force.
The engineer&#39;s role involves ...

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JoVE Core

Electrical Engineering

Unit 1

DC Circuit Analysis

KEY TERMS AND CONCEPTS

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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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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