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

In the bridge shown, V_s = 6 V, R₁ = 80 Ω and R₂ = 100 Ω. Find the voltage V_a of node a with respect to the negative supply rail.

V_s = 6 VR₁ = 80 ΩR₂ = 100 ΩR₃ = 250 ΩR₄ = 120 Ω

V_a = V

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 200 Ω, R₂ = 20 Ω and R₄ = 10 Ω. Find the setting R₃.

R₁ = 200 ΩR₂ = 20 ΩR₄ = 10 Ω

R₃ = Ω

3.Medium

A bridge has four 330 Ω arms and V_s = 12 V. The sensor R₂ increases by ΔR = 0.66 Ω. Using the small-change approximation, find the output V_ab in mV.

V_s = 12 VR = 330 ΩΔR = 0.66 Ω

V_ab = mV

4.Medium

A galvanometer with a resistance of 500 Ω is connected between a and b of the bridge shown (V_s = 15 V). Find the galvanometer current I_g from a to b, in µA.

V_s = 15 VR₁ = 40 ΩR₂ = 300 ΩR₃ = 400 ΩR₄ = 600 ΩR_g = 500 Ω

I_g = µA

5.Hard

A quarter bridge with one active gauge (GF = 2) is excited with 10 V. Under load the output reads 1 mV. Find the strain ε in µε.

V_s = 10 VGF = 2V_o = 1 mV

ε = µε

6.Hard

A quarter bridge with one active gauge (GF = 2) is excited with 3 V. Under load the output reads 0.9 mV. Find the strain ε in µε.

V_s = 3 VGF = 2V_o = 0.9 mV

ε = µε

Answer key

1. V_a = 3.333 V
2. R₃ = 100 Ω
3. V_ab = 6 mV
4. I_g = 5463 µA
5. ε = 200 µε
6. ε = 600 µε

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