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​ = 250 ΩR2​ = 10 ΩR3​ = 500 ΩR4​ = 500 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 2 V.

Vs = 2 VR1 = 250 ΩR2 = 10 ΩR3 = 500 ΩR4 = 500 Ω
Vab = V
2.Easy
+−5 VR1​ = 200 ΩR2​ = 20 ΩR3​ = ?R4​ = 100 ΩabG0

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 200 Ω, R₂ = 20 Ω and R₄ = 100 Ω. Find the setting R3.

R1 = 200 ΩR2 = 20 ΩR4 = 100 Ω
R3 = Ω
3.Medium
+−2 VR1​ = 40 ΩR2​ = 800 ΩR3​ = 1000 ΩR4​ = 60 ΩabGRg​ = 200 Ω

A galvanometer with a resistance of 200 Ω is connected between a and b of the bridge shown (Vs = 2 V). Find the galvanometer current Ig from a to b, in µA.

Vs = 2 VR1 = 40 ΩR2 = 800 ΩR3 = 1000 ΩR4 = 60 ΩRg = 200 Ω
Ig = µA
4.Medium
+−9 V1000 Ω1000 Ω + ΔR1000 Ω1000 Ωab+−254.7 mV

A bridge with four 1000 Ω arms is supplied with 9 V. When the sensor R₂ changes, the output reads Vab = 254.7 mV. Find the exact change ΔR of R₂.

Vs = 9 VR = 1000 ΩVab = 254.7 mV
ΔR = Ω
5.Hard
+−10 V1000 Ω1000 Ω + ΔR1000 Ω1000 Ωab+−1.25 mV

A strain gauge (GF = 2) on a member with E = 200 GPa forms a quarter bridge excited with 10 V. The output reads 1.25 mV. Find the axial stress σ in MPa.

Vs = 10 VGF = 2Vo = 1.25 mVE = 200 GPa
σ = MPa
6.Hard
+−10 V120 Ω120 Ω + ΔR120 Ω120 Ωab+−3.975 mV

A quarter bridge with one active gauge (GF = 2.12) is excited with 10 V. Under load the output reads 3.975 mV. Find the strain ε in µε.

Vs = 10 VGF = 2.12Vo = 3.975 mV
ε = µε

Answer key

  1. 1. Vab = −0.9231 V
  2. 2. R3 = 1000 Ω
  3. 3. Ig = 6079 µA
  4. 4. ΔR = 120 Ω
  5. 5. σ = 50 MPa
  6. 6. ε = 750 µε

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