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
+−10 VR1​ = 300 ΩR2​ = 300 ΩR3​ = 150 ΩR4​ = 60 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 10 V.

Vs = 10 VR1 = 300 ΩR2 = 300 ΩR3 = 150 ΩR4 = 60 Ω
Vab = V
2.Easy
+−12 VR1​ = 300 ΩR2​ = 60 ΩR3​ = ?R4​ = 150 ΩabG0

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 300 Ω, R₂ = 60 Ω and R₄ = 150 Ω. Find the setting R3.

R1 = 300 ΩR2 = 60 ΩR4 = 150 Ω
R3 = Ω
3.Medium
+−2 V100 Ω100 Ω + ΔR100 Ω100 Ωab+−Vab​ = ?

A bridge has four 100 Ω arms and Vs = 2 V. The sensor R₂ increases by ΔR = 0.8 Ω. Using the small-change approximation, find the output Vab in mV.

Vs = 2 VR = 100 ΩΔR = 0.8 Ω
Vab = mV
4.Medium
+−6 V150 Ω150 Ω + ΔR150 Ω150 Ωab+−Vab​ = ?

A bridge has four 150 Ω arms and Vs = 6 V. The sensor R₂ increases by ΔR = 0.375 Ω. Using the small-change approximation, find the output Vab in mV.

Vs = 6 VR = 150 ΩΔR = 0.375 Ω
Vab = mV
5.Hard
+−5 V120 Ω120 Ω + ΔR120 Ω120 Ωab+−2.625 mV

A quarter bridge with one active gauge (GF = 2.1) is excited with 5 V. Under load the output reads 2.625 mV. Find the strain ε in µε.

Vs = 5 VGF = 2.1Vo = 2.625 mV
ε = µε
6.Hard
+−5 V350 Ω − ΔR350 Ω + ΔR350 Ω350 Ωab+−Vo​ = ?

A bridge with 350 Ω arms is excited with 5 V and has two active gauges in adjacent arms, one in tension and one in compression (half bridge). The gauge factor is 2.1 and the strain is 400 µε. Find the bridge output Vo in mV.

Vs = 5 VGF = 2.1ε = 400 µε
Vo = mV

Answer key

  1. 1. Vab = 2.143 V
  2. 2. R3 = 750 Ω
  3. 3. Vab = 4 mV
  4. 4. Vab = 3.75 mV
  5. 5. ε = 1000 µε
  6. 6. Vo = 2.1 mV

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