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 = 60 Ω, R₂ = 150 Ω and R₄ = 80 Ω. Find the setting R₃.

R₁ = 60 ΩR₂ = 150 ΩR₄ = 80 Ω

R₃ = Ω

2.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 = 300 ΩR₂ = 500 ΩR₃ = 120 ΩR₄ = 100 Ω

V_ab = V

3.Medium

A bridge has four 100 Ω arms and V_s = 3 V. The sensor R₂ increases by ΔR = 5 Ω. Find the exact output V_ab in mV.

V_s = 3 VR = 100 ΩΔR = 5 Ω

V_ab = mV

4.Medium

A 300 Ω strain gauge is one arm (R₂) of a bridge with four equal 300 Ω arms and an excitation of 2 V. Find the power P_g dissipated in the gauge, in mW. Self-heating limits the excitation.

V_s = 2 VR = 300 Ω

P_g = mW

5.Hard

A quarter bridge with one active gauge (GF = 2.05) is excited with 10 V. Under load the output reads 3.844 mV. Find the strain ε in µε.

V_s = 10 VGF = 2.05V_o = 3.844 mV

ε = µε

6.Hard

A bridge with 120 Ω arms is excited with 5 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 200 µε. Find the bridge output V_o in mV.

V_s = 5 VGF = 2.05ε = 200 µε

V_o = mV

Answer key

1. R₃ = 32 Ω
2. V_ab = 0.5114 V
3. V_ab = 36.59 mV
4. P_g = 3.333 mW
5. ε = 750 µε
6. V_o = 1.025 mV

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