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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
+−2 VR1​ = 100 ΩR2​ = 250 ΩR3​ = ?R4​ = 50 ΩabG0

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 100 Ω, R₂ = 250 Ω and R₄ = 50 Ω. Find the setting R3.

R1 = 100 ΩR2 = 250 ΩR4 = 50 Ω
R3 = Ω
2.Easy
+−3 VR1​ = 20 ΩR2​ = 80 ΩR3​ = 200 ΩR4​ = 150 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 3 V.

Vs = 3 VR1 = 20 ΩR2 = 80 ΩR3 = 200 ΩR4 = 150 Ω
Vab = V
3.Medium
+−2 V120 Ω120 Ω + ΔR120 Ω120 Ωab+−24.39 mV

A bridge with four 120 Ω arms is supplied with 2 V. When the sensor R₂ changes, the output reads Vab = 24.39 mV. Find the exact change ΔR of R₂.

Vs = 2 VR = 120 ΩVab = 24.39 mV
ΔR = Ω
4.Medium
+−3 V350 Ω350 Ω + ΔR350 Ω350 Ωab+−Vab​ = ?

A bridge has four 350 Ω arms and Vs = 3 V. The sensor R₂ increases by ΔR = 52.5 Ω. Find the exact output Vab in mV.

Vs = 3 VR = 350 ΩΔR = 52.5 Ω
Vab = mV
5.Hard
+−2.5 V120 Ω120 Ω + ΔR120 Ω120 Ωab+−Vo​ = ?

A bridge with 120 Ω arms is excited with 2.5 V and has one active gauge (quarter bridge). The gauge factor is 2.1 and the strain is 1000 µε. Find the bridge output Vo in mV.

Vs = 2.5 VGF = 2.1ε = 1000 µε
Vo = mV
6.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 0.861 Ω. Find the strain ε in microstrain (µε).

R = 350 ΩGF = 2.05ΔR = 0.861 Ω
ε = µε

Answer key

  1. 1. R3 = 20 Ω
  2. 2. Vab = 1.114 V
  3. 3. ΔR = 6 Ω
  4. 4. Vab = 104.7 mV
  5. 5. Vo = 1.313 mV
  6. 6. ε = 1200 µε

Full step-by-step solutions: practise this topic on examproblems.com.