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

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 200 Ω, R₂ = 300 Ω and R₄ = 300 Ω. Find the setting R₃.

R₁ = 200 ΩR₂ = 300 ΩR₄ = 300 Ω

R₃ = Ω

2.Easy

Find the open-circuit output voltage V_ab = V_a − V_b of the bridge shown, with V_s = 5 V.

V_s = 5 VR₁ = 300 ΩR₂ = 100 ΩR₃ = 20 ΩR₄ = 150 Ω

V_ab = V

3.Medium

Find the Thévenin resistance R_th of the bridge shown, seen from the output terminals a and b.

V_s = 2 VR₁ = 400 ΩR₂ = 20 ΩR₃ = 50 ΩR₄ = 400 Ω

R_th = Ω

4.Medium

A bridge has four 300 Ω arms and V_s = 12 V. The sensor R₂ increases by ΔR = 45 Ω. Find the exact output V_ab in mV.

V_s = 12 VR = 300 ΩΔR = 45 Ω

V_ab = mV

5.Hard

A strain gauge (GF = 2.12) on a member with E = 110 GPa forms a quarter bridge excited with 3 V. The output reads 2.385 mV. Find the axial stress σ in MPa.

V_s = 3 VGF = 2.12V_o = 2.385 mVE = 110 GPa

σ = MPa

6.Hard

A bridge with 350 Ω arms is excited with 10 V and has four active gauges, two in tension and two in compression (full bridge). The gauge factor is 2 and the strain is 500 µε. Find the bridge output V_o in mV.

V_s = 10 VGF = 2ε = 500 µε

V_o = mV

Answer key

1. R₃ = 200 Ω
2. V_ab = −3.162 V
3. R_th = 63.49 Ω
4. V_ab = 418.6 mV
5. σ = 165 MPa
6. V_o = 10 mV

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