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
+−15 VR1​ = 300 ΩR2​ = 120 ΩR3​ = 40 ΩR4​ = ?abG0

The Wheatstone bridge in the diagram is balanced: the galvanometer reads zero. R₁ = 300 Ω, R₂ = 120 Ω and R₃ = 40 Ω. Find the unknown resistor R4.

R1 = 300 ΩR2 = 120 ΩR3 = 40 Ω
R4 = Ω
2.Easy
+−10 VR1​ = 250 ΩR2​ = 250 ΩR3​ = 120 ΩR4​ = ?abG0

The Wheatstone bridge in the diagram is balanced: the galvanometer reads zero. R₁ = 250 Ω, R₂ = 250 Ω and R₃ = 120 Ω. Find the unknown resistor R4.

R1 = 250 ΩR2 = 250 ΩR3 = 120 Ω
R4 = Ω
3.Medium
+−2 V470 Ω470 Ω + ΔR470 Ω470 Ωab+−19.61 mV

A bridge with four 470 Ω arms is supplied with 2 V. When the sensor R₂ changes, the output reads Vab = 19.61 mV. Find the exact change ΔR of R₂.

Vs = 2 VR = 470 ΩVab = 19.61 mV
ΔR = Ω
4.Medium
+−3 V200 Ω200 Ω + ΔR200 Ω200 Ωab+−Vab​ = ?

A bridge has four 200 Ω arms and Vs = 3 V. The sensor R₂ increases by ΔR = 20 Ω. Find the exact output Vab in mV.

Vs = 3 VR = 200 ΩΔR = 20 Ω
Vab = mV
5.Hard
+−5 V1000 Ω1000 Ω + ΔR1000 Ω1000 Ωab+−Vo​

A quarter bridge (one active gauge, GF = 2) is excited with 5 V. The largest strain to be measured is 600 µε, and it must give 2.5 V at the input of an analogue-to-digital converter. Find the amplifier gain G.

Vs = 5 VGF = 2εmax = 600 µεVFS = 2.5 V
G =
6.Hard
+−10 V350 Ω − ΔR350 Ω + ΔR350 Ω350 Ωab+−Vo​ = ?

A bridge with 350 Ω arms is excited with 10 V and has two active gauges in adjacent arms, one in tension and one in compression (half bridge). The gauge factor is 2.05 and the strain is 1500 µε. Find the bridge output Vo in mV.

Vs = 10 VGF = 2.05ε = 1500 µε
Vo = mV

Answer key

  1. 1. R4 = 16 Ω
  2. 2. R4 = 120 Ω
  3. 3. ΔR = 18.8 Ω
  4. 4. Vab = 71.43 mV
  5. 5. G = 1667
  6. 6. Vo = 15.38 mV

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