Wheatstone bridge & strain gauges worksheet with answers

Free printable Wheatstone bridge & strain gauges worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
+−15 VR1​ = 120 ΩR2​ = 80 ΩR3​ = 800 ΩR4​ = 10 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 15 V.

Vs = 15 VR1 = 120 ΩR2 = 80 ΩR3 = 800 ΩR4 = 10 Ω
Vab = V
2.Easy
+−5 VR1​ = 10 ΩR2​ = 50 ΩR3​ = 800 ΩR4​ = 300 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 5 V.

Vs = 5 VR1 = 10 ΩR2 = 50 ΩR3 = 800 ΩR4 = 300 Ω
Vab = V
3.Medium
+−10 V220 Ω220 Ω + ΔR220 Ω220 Ωab+−Vab​ = ?

A bridge has four 220 Ω arms and Vs = 10 V. The sensor R₂ increases by ΔR = 22 Ω. Find the exact output Vab in mV.

Vs = 10 VR = 220 ΩΔR = 22 Ω
Vab = mV
4.Medium
+−2 V300 Ω300 Ω + ΔR300 Ω300 Ωab+−Vab​ = ?

A bridge has four 300 Ω arms and Vs = 2 V. The sensor R₂ increases by ΔR = 24 Ω. Find the exact output Vab in mV.

Vs = 2 VR = 300 ΩΔR = 24 Ω
Vab = mV
5.Hard
+−10 V350 Ω350 Ω + ΔR350 Ω350 Ωab+−1.281 mV

A strain gauge (GF = 2.05) on a member with E = 70 GPa forms a quarter bridge excited with 10 V. The output reads 1.281 mV. Find the axial stress σ in MPa.

Vs = 10 VGF = 2.05Vo = 1.281 mVE = 70 GPa
σ = MPa
6.Hard
+−V120 Ω120 Ω + ΔR120 Ω120 Ωab+−

A 120 Ω strain gauge with gauge factor 2 is bonded to a steel bar. Under load its resistance rises by 0.048 Ω. Find the strain ε in microstrain (µε).

R = 120 ΩGF = 2ΔR = 0.048 Ω
ε = µε

Answer key

  1. 1. Vab = 5.815 V
  2. 2. Vab = 2.803 V
  3. 3. Vab = 238.1 mV
  4. 4. Vab = 38.46 mV
  5. 5. σ = 17.5 MPa
  6. 6. ε = 200 µε

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