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 worksheet Practise 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

The Wheatstone bridge in the diagram is balanced: the galvanometer reads zero. R₁ = 200 Ω, R₂ = 40 Ω and R₃ = 1000 Ω. Find the unknown resistor R₄.

R₁ = 200 ΩR₂ = 40 ΩR₃ = 1000 Ω

R₄ = Ω

2.Easy

In the bridge shown, V_s = 10 V, R₁ = 80 Ω and R₂ = 150 Ω. Find the voltage V_a of node a with respect to the negative supply rail.

V_s = 10 VR₁ = 80 ΩR₂ = 150 ΩR₃ = 300 ΩR₄ = 500 Ω

V_a = V

3.Medium

A bridge has four 100 Ω arms and V_s = 12 V. The sensor R₂ increases by ΔR = 10 Ω. Find the exact output V_ab in mV.

V_s = 12 VR = 100 ΩΔR = 10 Ω

V_ab = mV

4.Medium

A bridge has four 300 Ω arms and V_s = 2 V. The sensor R₂ increases by ΔR = 75 Ω. Find the exact output V_ab in mV.

V_s = 2 VR = 300 ΩΔR = 75 Ω

V_ab = mV

5.Hard

A 350 Ω strain gauge with gauge factor 2 is bonded to a steel bar. Under load its resistance rises by 0.14 Ω. Find the strain ε in microstrain (µε).

R = 350 ΩGF = 2ΔR = 0.14 Ω

ε = µε

6.Hard

A strain gauge (GF = 2.1) on a member with E = 70 GPa forms a quarter bridge excited with 3 V. The output reads 1.181 mV. Find the axial stress σ in MPa.

V_s = 3 VGF = 2.1V_o = 1.181 mVE = 70 GPa

σ = MPa

Answer key

1. R₄ = 200 Ω
2. V_a = 6.522 V
3. V_ab = 285.7 mV
4. V_ab = 111.1 mV
5. ε = 200 µε
6. σ = 52.49 MPa

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