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.

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1.Easy
+−15 VR1​ = 40 ΩR2​ = 20 ΩR3​ = 120 ΩR4​ = 100 Ωab+−Vab​ = ?

Find the open-circuit output voltage Vab = Va − Vb of the bridge shown, with Vs = 15 V.

Vs = 15 VR1 = 40 ΩR2 = 20 ΩR3 = 120 ΩR4 = 100 Ω
Vab = V
2.Easy
+−5 VR1​ = 150 ΩR2​ = 400 ΩR3​ = ?R4​ = 600 ΩabG0

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 150 Ω, R₂ = 400 Ω and R₄ = 600 Ω. Find the setting R3.

R1 = 150 ΩR2 = 400 ΩR4 = 600 Ω
R3 = Ω
3.Medium
+−10 V150 Ω150 Ω150 Ω150 Ωab+−

A 150 Ω strain gauge is one arm (R₂) of a bridge with four equal 150 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 = 150 Ω
Pg = mW
4.Medium
+−2 V470 Ω470 Ω470 Ω470 Ωab+−

A 470 Ω strain gauge is one arm (R₂) of a bridge with four equal 470 Ω arms and an excitation of 2 V. Find the power Pg dissipated in the gauge, in mW. Self-heating limits the excitation.

Vs = 2 VR = 470 Ω
Pg = mW
5.Hard
+−3 V120 Ω120 Ω + ΔR120 Ω120 Ωab+−Vo​ = ?

A bridge with 120 Ω arms is excited with 3 V and has one active gauge (quarter bridge). The gauge factor is 2.05 and the strain is 800 µε. Find the bridge output Vo in mV.

Vs = 3 VGF = 2.05ε = 800 µε
Vo = mV
6.Hard
+−10 V120 Ω − ΔR120 Ω + ΔR120 Ω120 Ωab+−Vo​ = ?

A bridge with 120 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 and the strain is 1200 µε. Find the bridge output Vo in mV.

Vs = 10 VGF = 2ε = 1200 µε
Vo = mV

Answer key

  1. 1. Vab = −1.818 V
  2. 2. R3 = 225 Ω
  3. 3. Pg = 166.7 mW
  4. 4. Pg = 2.128 mW
  5. 5. Vo = 1.23 mV
  6. 6. Vo = 12 mV

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