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
+−3 VR1​ = 500 ΩR2​ = 500 ΩR3​ = ?R4​ = 20 ΩabG0

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 500 Ω, R₂ = 500 Ω and R₄ = 20 Ω. Find the setting R3.

R1 = 500 ΩR2 = 500 ΩR4 = 20 Ω
R3 = Ω
2.Easy
+−9 VR1​ = 80 ΩR2​ = 80 ΩR3​ = 300 ΩR4​ = 50 Ωab+−

The bridge shown is supplied with Vs = 9 V and its output is open. Find the current Is drawn from the supply, in mA.

Vs = 9 VR1 = 80 ΩR2 = 80 ΩR3 = 300 ΩR4 = 50 Ω
Is = mA
3.Medium
+−6 V1000 Ω1000 Ω + ΔR1000 Ω1000 Ωab+−Vab​ = ?

A bridge has four 1000 Ω arms and Vs = 6 V. The sensor R₂ increases by ΔR = 80 Ω. Find the exact output Vab in mV.

Vs = 6 VR = 1000 ΩΔR = 80 Ω
Vab = mV
4.Medium
+−5 V1000 Ω1000 Ω + ΔR1000 Ω1000 Ωab+−60.98 mV

A bridge with four 1000 Ω arms is supplied with 5 V. When the sensor R₂ changes, the output reads Vab = 60.98 mV. Find the exact change ΔR of R₂.

Vs = 5 VR = 1000 ΩVab = 60.98 mV
ΔR = Ω
5.Hard
+−10 V1000 Ω1000 Ω + ΔR1000 Ω1000 Ωab+−Vo​ = ?

A bridge with 1000 Ω arms is excited with 10 V and has one active gauge (quarter bridge). The gauge factor is 2.1 and the strain is 1500 µε. Find the bridge output Vo in mV.

Vs = 10 VGF = 2.1ε = 1500 µε
Vo = mV
6.Hard
+−3 V1000 Ω1000 Ω + ΔR1000 Ω1000 Ωab+−Vo​ = ?

A bridge with 1000 Ω arms is excited with 3 V and has one active gauge (quarter bridge). The gauge factor is 2.1 and the strain is 1500 µε. Find the bridge output Vo in mV.

Vs = 3 VGF = 2.1ε = 1500 µε
Vo = mV

Answer key

  1. 1. R3 = 20 Ω
  2. 2. Is = 81.96 mA
  3. 3. Vab = 115.4 mV
  4. 4. ΔR = 50 Ω
  5. 5. Vo = 7.875 mV
  6. 6. Vo = 2.363 mV

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