11.1.11

Strain Gauges

Test yourself

Strain Gauges

Strain gauges are used to measure the strain of different materials by measuring changes in their resistance.

Illustrative background for StructureIllustrative background for Structure ?? "content

Structure

  • A strain gauge consists of a thin metal wire that is sealed into a thin layer by a flexible, insulating material.
  • The strain gauge is then connected to a circuit in order to make measurements.
Illustrative background for MeasurementsIllustrative background for Measurements ?? "content

Measurements

  • The voltage and current of the circuit are measured both when the strain gauge is stretched and unstretched.
  • The change in resistance of the strain gauge is then given by the equation:
    • ΔR=ρΔLA\Delta R = \frac{\large \rho\Delta L}{\large A}
  • Where LL is the change in length of the wire, ρ\rho is the resistivity of the material and AA is the cross-sectional area of the wire.
  • The change in cross-sectional area as the strain gauge (and wire) is stretched is assumed to be constant.
Illustrative background for StrainIllustrative background for Strain ?? "content

Strain

  • Recall that the strain is given by the equation:
    • strain=ΔLL\text{strain}= \frac{\Delta L}{L}
  • So the change in resistance of the strain gauge is proportional to the strain.
    • ΔRstrain\Delta R \propto \text{strain}

Jump to other topics

1Physical Quantities & Units

2Measurement Techniques

3Kinematics

4Dynamics

5Gravitational Fields

6Deformation of Solids

7Thermal Physics

8Oscillations

9Communication

10Electric Fields

11Current Electricity

12Magnetic Fields

13Modern Physics

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium