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

Find the open-circuit output voltage V_ab = V_a − V_b of the bridge shown, with V_s = 3 V.

V_s = 3 VR₁ = 800 ΩR₂ = 120 ΩR₃ = 200 ΩR₄ = 40 Ω

V_ab = V

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 20 Ω, R₂ = 500 Ω and R₄ = 800 Ω. Find the setting R₃.

R₁ = 20 ΩR₂ = 500 ΩR₄ = 800 Ω

R₃ = Ω

3.Medium

A 250 Ω strain gauge is one arm (R₂) of a bridge with four equal 250 Ω arms and an excitation of 6 V. Find the power P_g dissipated in the gauge, in mW. Self-heating limits the excitation.

V_s = 6 VR = 250 Ω

P_g = mW

4.Medium

A bridge has four 1000 Ω arms and V_s = 5 V. The sensor R₂ increases by ΔR = 100 Ω. Find the exact output V_ab in mV.

V_s = 5 VR = 1000 ΩΔR = 100 Ω

V_ab = mV

5.Hard

A bridge with 120 Ω arms is excited with 5 V and has one active gauge (quarter bridge). The gauge factor is 2 and the strain is 400 µε. Find the bridge output V_o in mV.

V_s = 5 VGF = 2ε = 400 µε

V_o = mV

6.Hard

A strain gauge (GF = 2) on a member with E = 70 GPa forms a quarter bridge excited with 2.5 V. The output reads 0.75 mV. Find the axial stress σ in MPa.

V_s = 2.5 VGF = 2V_o = 0.75 mVE = 70 GPa

σ = MPa

Answer key

1. V_ab = −0.1087 V
2. R₃ = 32 Ω
3. P_g = 36 mW
4. V_ab = 119 mV
5. V_o = 1 mV
6. σ = 42 MPa

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