Question about using a wheatstone bridge to measure changes in resistance

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SUMMARY

The discussion centers on the use of a Wheatstone bridge for measuring small changes in resistance in strain gauges. It is established that a Wheatstone bridge is preferred over a milliammeter due to its ability to compensate for temperature variations, which is crucial when measuring resistance changes in materials. The setup involves using four gauges, with two attached to the specimen and two unstrained, ensuring accurate readings despite temperature fluctuations. Therefore, for experiments focused on resistance variation with temperature, utilizing a Wheatstone bridge is essential for precision.

PREREQUISITES
  • Understanding of Wheatstone bridge circuits
  • Knowledge of strain gauge operation and characteristics
  • Familiarity with temperature compensation techniques
  • Basic principles of electrical resistance and Ohm's Law
NEXT STEPS
  • Study the design and operation of Wheatstone bridge circuits
  • Explore temperature compensation methods for strain gauges
  • Learn about different types of strain gauges and their applications
  • Investigate the impact of temperature on electrical resistance
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Electrical engineers, experimental physicists, and researchers involved in materials testing or sensor technology will benefit from this discussion.

gionex
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Hi

I need to measure the small changes in resistance of a strain gauge.

I have read that a wheatstone bridge circuit is used to do this.. but I don't understand why I can't just use a milliammeter to measure the change in current through the strain gauge and then use R=V/I to find the new resistance/change in resistance. Sorry if it's a stupid question, but could someone please explain why a wheatstone bridge is used?

thanks.
 
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From Wikipedia:
Even with strain gauges that are not self-temperature compensated (such as isoelastic alloy), using a Wheatstone bridge arrangement it is possible to compensate for temperature changes in the specimen under test and the strain gauge. To do this in a Wheatstone bridge made of four gauges, two gauges are attached to the specimen, and two are left unattached, unstrained, and at the same temperature as the specimen and the attached gauges
 
so you are saying the only reason to use a wheatstone bridge is to remove the effect of temperature?
In my experiment, I need to measure how the resistance of a strain gauge varies with changes to the temperature of the specimen material, so does this mean I do not need to use a wheatstone bridge?
 
anyone? :z
 
i need help on this one aswell...have u started yet
 

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