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 bridge shown is supplied with V_s = 5 V and its output is open. Find the current I_s drawn from the supply, in mA.

V_s = 5 VR₁ = 400 ΩR₂ = 120 ΩR₃ = 500 ΩR₄ = 20 Ω

I_s = mA

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 20 Ω, R₂ = 500 Ω and R₄ = 50 Ω. Find the setting R₃.

R₁ = 20 ΩR₂ = 500 ΩR₄ = 50 Ω

R₃ = Ω

3.Medium

A bridge has four 1000 Ω arms and V_s = 15 V. The sensor R₂ increases by ΔR = 100 Ω. Find the exact output V_ab in mV.

V_s = 15 VR = 1000 ΩΔR = 100 Ω

V_ab = mV

4.Medium

A bridge has four 120 Ω arms and V_s = 15 V. The sensor R₂ increases by ΔR = 0.24 Ω. Using the small-change approximation, find the output V_ab in mV.

V_s = 15 VR = 120 ΩΔR = 0.24 Ω

V_ab = mV

5.Hard

A 120 Ω strain gauge with gauge factor 2.12 is bonded to a steel bar. Under load its resistance rises by 0.3053 Ω. Find the strain ε in microstrain (µε).

R = 120 ΩGF = 2.12ΔR = 0.3053 Ω

ε = µε

6.Hard

A 120 Ω strain gauge with gauge factor 2.05 is bonded to a steel bar. Under load its resistance rises by 0.246 Ω. Find the strain ε in microstrain (µε).

R = 120 ΩGF = 2.05ΔR = 0.246 Ω

ε = µε

Answer key

1. I_s = 19.23 mA
2. R₃ = 2 Ω
3. V_ab = 357.1 mV
4. V_ab = 7.5 mV
5. ε = 1200 µε
6. ε = 1000 µε

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