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
+−9 VR1​ = 500 ΩR2​ = 600 ΩR3​ = 400 ΩR4​ = 800 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 9 V.

Vs = 9 VR1 = 500 ΩR2 = 600 ΩR3 = 400 ΩR4 = 800 Ω
Vab = V
2.Easy
+−12 VR1​ = 200 ΩR2​ = 50 ΩR3​ = 10 ΩR4​ = 80 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 12 V.

Vs = 12 VR1 = 200 ΩR2 = 50 ΩR3 = 10 ΩR4 = 80 Ω
Vab = V
3.Medium
+−5 V500 Ω500 Ω500 Ω500 Ωab+−

A 500 Ω strain gauge is one arm (R₂) of a bridge with four equal 500 Ω arms and an excitation of 5 V. Find the power Pg dissipated in the gauge, in mW. Self-heating limits the excitation.

Vs = 5 VR = 500 Ω
Pg = mW
4.Medium
+−15 V400 Ω400 Ω + ΔR400 Ω400 Ωab+−Vab​ = ?

A bridge has four 400 Ω arms and Vs = 15 V. The sensor R₂ increases by ΔR = 40 Ω. Find the exact output Vab in mV.

Vs = 15 VR = 400 ΩΔR = 40 Ω
Vab = mV
5.Hard
+−V350 Ω350 Ω + ΔR350 Ω350 Ωab+−

A 350 Ω strain gauge with gauge factor 2.05 is bonded to a steel bar. Under load its resistance rises by 0.5381 Ω. Find the strain ε in microstrain (µε).

R = 350 ΩGF = 2.05ΔR = 0.5381 Ω
ε = µε
6.Hard
+−2.5 V350 Ω350 Ω + ΔR350 Ω350 Ωab+−0.331 mV

A quarter bridge with one active gauge (GF = 2.12) is excited with 2.5 V. Under load the output reads 0.331 mV. Find the strain ε in µε.

Vs = 2.5 VGF = 2.12Vo = 0.331 mV
ε = µε

Answer key

  1. 1. Vab = −1.091 V
  2. 2. Vab = −8.267 V
  3. 3. Pg = 12.5 mW
  4. 4. Vab = 357.1 mV
  5. 5. ε = 750 µε
  6. 6. ε = 249.8 µε

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