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
+−3 VR1​ = 120 ΩR2​ = 250 ΩR3​ = ?R4​ = 300 ΩabG0

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 120 Ω, R₂ = 250 Ω and R₄ = 300 Ω. Find the setting R3.

R1 = 120 ΩR2 = 250 ΩR4 = 300 Ω
R3 = Ω
2.Easy
+−12 VR1​ = 20 ΩR2​ = 300 ΩR3​ = 40 ΩR4​ = 1000 Ωab+−

In the bridge shown, Vs = 12 V, R₁ = 20 Ω and R₂ = 300 Ω. Find the voltage Va of node a with respect to the negative supply rail.

Vs = 12 VR1 = 20 ΩR2 = 300 ΩR3 = 40 ΩR4 = 1000 Ω
Va = V
3.Medium
+−6 V250 Ω250 Ω + ΔR250 Ω250 Ωab+−Vab​ = ?

A bridge has four 250 Ω arms and Vs = 6 V. The sensor R₂ increases by ΔR = 50 Ω. Find the exact output Vab in mV.

Vs = 6 VR = 250 ΩΔR = 50 Ω
Vab = mV
4.Medium
+−3 V400 Ω400 Ω + ΔR400 Ω400 Ωab+−Vab​ = ?

A bridge has four 400 Ω arms and Vs = 3 V. The sensor R₂ increases by ΔR = 0.4 Ω. Using the small-change approximation, find the output Vab in mV.

Vs = 3 VR = 400 ΩΔR = 0.4 Ω
Vab = mV
5.Hard
+−2.5 V350 Ω − ΔR350 Ω + ΔR350 Ω + ΔR350 Ω − ΔRab+−Vo​ = ?

A bridge with 350 Ω arms is excited with 2.5 V and has four active gauges, two in tension and two in compression (full bridge). The gauge factor is 2.12 and the strain is 800 µε. Find the bridge output Vo in mV.

Vs = 2.5 VGF = 2.12ε = 800 µε
Vo = mV
6.Hard
+−12 V120 Ω − ΔR120 Ω + ΔR120 Ω + ΔR120 Ω − ΔRab+−Vo​ = ?

A load cell (a full bridge of strain gauges) has a rated output of 1 mV/V at its rated load of 50 kg. It is excited with 12 V. Find its output Vo under a load of 10 kg.

1 mV/VFrated = 50 kgVs = 12 VF = 10 kg
Vo = mV

Answer key

  1. 1. R3 = 144 Ω
  2. 2. Va = 11.25 V
  3. 3. Vab = 272.7 mV
  4. 4. Vab = 0.75 mV
  5. 5. Vo = 4.24 mV
  6. 6. Vo = 2.4 mV

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