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A very quick query about strain gauges

  1. Jan 3, 2004 #1


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    I am doing a project on strain gauges. I have the thing set up in a half-wheatstone bridge. Using a pair of strain gauges im trying to measure the weight!!(attaching each one to a side of a ruler/cantilever and bending it by attaching weight to the end)

    So heres a confusing bit. I no when the gauges are unstrained the reading on the bridge shud be ZERO(i.e bridge is balanced) I'm measuring the voltage difference across the bridge not current. The point is when i bend them i get a reading(which i shud)

    Am i correct in assuming that the resistance difference across the bridge when i bend it. This will b recorded as a voltage change?
    SO heres a question. If i bend it more the resistance difference should b greater so should i get a bigger reading (voltmeter) on the scales or not??

    I no the explaination isnt a perfect . PLease bear with me.
  2. jcsd
  3. Jan 4, 2004 #2


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    Staff Emeritus
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    What voltage are you measuring?

    If I recall correctly a Wheatstone bridge relies on current measurements. If one arm is out of balance, a current will flow through the center, you then adjust the resistance in the arm opposite the load to zero the current.

    You may want to check into a spell checker, while it is possible to figure out what you are trying to say, frequently I will simply go to the next message rather then attempt to figure out something as poorly written as your message.
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