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 = 1000 Ω, R₂ = 60 Ω and R₃ = 250 Ω. Find the unknown resistor R₄.

R₁ = 1000 ΩR₂ = 60 ΩR₃ = 250 Ω

R₄ = Ω

2.Easy

Find the open-circuit output voltage V_ab = V_a − V_b of the bridge shown, with V_s = 2 V.

V_s = 2 VR₁ = 100 ΩR₂ = 100 ΩR₃ = 200 ΩR₄ = 300 Ω

V_ab = V

3.Medium

A bridge has four 100 Ω arms and V_s = 10 V. The sensor R₂ increases by ΔR = 15 Ω. Find the exact output V_ab in mV.

V_s = 10 VR = 100 ΩΔR = 15 Ω

V_ab = mV

4.Medium

A 470 Ω strain gauge is one arm (R₂) of a bridge with four equal 470 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 = 470 Ω

P_g = mW

5.Hard

A strain gauge (GF = 2) on a member with E = 200 GPa forms a quarter bridge excited with 5 V. The output reads 1.5 mV. Find the axial stress σ in MPa.

V_s = 5 VGF = 2V_o = 1.5 mVE = 200 GPa

σ = MPa

6.Hard

A bridge with 120 Ω arms is excited with 3 V and has two active gauges in adjacent arms, one in tension and one in compression (half bridge). The gauge factor is 2.05 and the strain is 1200 µε. Find the bridge output V_o in mV.

V_s = 3 VGF = 2.05ε = 1200 µε

V_o = mV

Answer key

1. R₄ = 15 Ω
2. V_ab = −0.2 V
3. V_ab = 348.8 mV
4. P_g = 19.15 mW
5. σ = 120 MPa
6. V_o = 3.69 mV

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