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 = 2 V.

V_s = 2 VR₁ = 400 ΩR₂ = 150 ΩR₃ = 500 ΩR₄ = 800 Ω

V_ab = V

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 20 Ω, R₂ = 10 Ω and R₄ = 60 Ω. Find the setting R₃.

R₁ = 20 ΩR₂ = 10 ΩR₄ = 60 Ω

R₃ = Ω

3.Medium

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

V_s = 9 VR₁ = 80 ΩR₂ = 500 ΩR₃ = 50 ΩR₄ = 60 Ω

R_th = Ω

4.Medium

A bridge with four 500 Ω arms is supplied with 9 V. When the sensor R₂ changes, the output reads V_ab = 254.7 mV. Find the exact change ΔR of R₂.

V_s = 9 VR = 500 ΩV_ab = 254.7 mV

ΔR = Ω

5.Hard

A quarter bridge (one active gauge, GF = 2.1) is excited with 3 V. The largest strain to be measured is 1500 µε, and it must give 10 V at the input of an analogue-to-digital converter. Find the amplifier gain G.

V_s = 3 VGF = 2.1ε_max = 1500 µεV_FS = 10 V

G =

6.Hard

A 1000 Ω strain gauge with gauge factor 2 is bonded to a steel bar. Under load its resistance rises by 1 Ω. Find the strain ε in microstrain (µε).

R = 1000 ΩGF = 2ΔR = 1 Ω

ε = µε

Answer key

1. V_ab = −0.6853 V
2. R₃ = 120 Ω
3. R_th = 96.24 Ω
4. ΔR = 60 Ω
5. G = 4233
6. ε = 500 µε

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