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
+−6 VR1​ = 150 ΩR2​ = 300 ΩR3​ = ?R4​ = 100 ΩabG0

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 150 Ω, R₂ = 300 Ω and R₄ = 100 Ω. Find the setting R3.

R1 = 150 ΩR2 = 300 ΩR4 = 100 Ω
R3 = Ω
2.Easy
100 ΩRₓBGACD60 cm

In a slide-wire (metre) bridge a known 100 Ω resistor sits in the left gap and an unknown resistor Rₓ in the right gap. The galvanometer reads zero when the jockey is 60 cm from the left end A of the 100 cm wire. Find Rx.

R = 100 Ωl = 60 cmL = 100 cm
Rx = Ω
3.Medium
+−6 V400 Ω400 Ω + ΔR400 Ω400 Ωab+−142.9 mV

A bridge with four 400 Ω arms is supplied with 6 V. When the sensor R₂ changes, the output reads Vab = 142.9 mV. Find the exact change ΔR of R₂.

Vs = 6 VR = 400 ΩVab = 142.9 mV
ΔR = Ω
4.Medium
+−10 V200 Ω200 Ω200 Ω200 Ωab+−

A 200 Ω strain gauge is one arm (R₂) of a bridge with four equal 200 Ω arms and an excitation of 10 V. Find the power Pg dissipated in the gauge, in mW. Self-heating limits the excitation.

Vs = 10 VR = 200 Ω
Pg = mW
5.Hard
+−2.5 V350 Ω350 Ω + ΔR350 Ω350 Ωab+−Vo​

A quarter bridge (one active gauge, GF = 2.1) is excited with 2.5 V. The largest strain to be measured is 1200 µε, and it must give 2.5 V at the input of an analogue-to-digital converter. Find the amplifier gain G.

Vs = 2.5 VGF = 2.1εmax = 1200 µεVFS = 2.5 V
G =
6.Hard
+−V350 Ω350 Ω + ΔR350 Ω350 Ωab+−

A 350 Ω strain gauge with gauge factor 2.12 is bonded to a steel bar. Under load its resistance rises by 0.4452 Ω. Find the strain ε in microstrain (µε).

R = 350 ΩGF = 2.12ΔR = 0.4452 Ω
ε = µε

Answer key

  1. 1. R3 = 50 Ω
  2. 2. Rx = 66.67 Ω
  3. 3. ΔR = 40 Ω
  4. 4. Pg = 125 mW
  5. 5. G = 1587
  6. 6. ε = 600 µε

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