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

Find the open-circuit output voltage V_ab = V_a − V_b of the bridge shown, with V_s = 9 V.

V_s = 9 VR₁ = 300 ΩR₂ = 60 ΩR₃ = 120 ΩR₄ = 200 Ω

V_ab = V

2.Easy

In the bridge shown, V_s = 12 V, R₁ = 1000 Ω and R₂ = 80 Ω. Find the voltage V_a of node a with respect to the negative supply rail.

V_s = 12 VR₁ = 1000 ΩR₂ = 80 ΩR₃ = 600 ΩR₄ = 50 Ω

V_a = V

3.Medium

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

V_s = 12 VR₁ = 200 ΩR₂ = 300 ΩR₃ = 50 ΩR₄ = 60 Ω

R_th = Ω

4.Medium

A bridge with four 470 Ω arms is supplied with 3 V. When the sensor R₂ changes, the output reads V_ab = 84.91 mV. Find the exact change ΔR of R₂.

V_s = 3 VR = 470 ΩV_ab = 84.91 mV

ΔR = Ω

5.Hard

A quarter bridge with one active gauge (GF = 2.12) is excited with 2.5 V. Under load the output reads 0.663 mV. Find the strain ε in µε.

V_s = 2.5 VGF = 2.12V_o = 0.663 mV

ε = µε

6.Hard

A 350 Ω strain gauge with gauge factor 2 is bonded to a steel bar. Under load its resistance rises by 0.525 Ω. Find the strain ε in microstrain (µε).

R = 350 ΩGF = 2ΔR = 0.525 Ω

ε = µε

Answer key

1. V_ab = −4.125 V
2. V_a = 0.8889 V
3. R_th = 147.3 Ω
4. ΔR = 56.4 Ω
5. ε = 500.4 µε
6. ε = 750 µε

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