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Question about using a wheatstone bridge to measure changes in resistance

  • Thread starter gionex
  • Start date
  • #1
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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.
 

Answers and Replies

  • #2
45
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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
 
  • #3
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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?
 
  • #4
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anyone? :z
 
  • #5
3
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i need help on this one aswell....have u started yet
 

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