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AC Excited Wheatstone Bridge

  1. Oct 8, 2013 #1
    I have a torque meter using a full-bridge Wheatstone bridge (all legs are strain gauges). The bridge has some non-zero, unknown offset (it's old). I would like to strip this offset out prior to signal amplification.

    My theory is, under DC conditions, the offset exists, which mucks up the output response (need compensation). If I excite the bridge with AC, will the offset appear as a DC offset present in the response sinusoid? Then, with applied torque, the amplitude of the response signal will change, while the offset is now decoupled from the response sinusoid?

    Then, will applied load cause a further offset of the AC signal, or will it cause an amplitude change of the sinusoid? Ideally, I want to automatically strip out the DC offset (AC coupled signal with carrier wave) while preserving the displacement data.

    Am I close here or way off in left field? Before I start working with components, I want to make sure my theory is correct. Thanks!
  2. jcsd
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