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 = 3 V.

V_s = 3 VR₁ = 40 ΩR₂ = 300 ΩR₃ = 40 ΩR₄ = 80 Ω

V_ab = V

2.Easy

Find the open-circuit output voltage V_ab = V_a − V_b of the bridge shown, with V_s = 15 V.

V_s = 15 VR₁ = 800 ΩR₂ = 60 ΩR₃ = 20 ΩR₄ = 50 Ω

V_ab = V

3.Medium

A bridge has four 330 Ω arms and V_s = 10 V. The sensor R₂ increases by ΔR = 33 Ω. Find the exact output V_ab in mV.

V_s = 10 VR = 330 ΩΔR = 33 Ω

V_ab = mV

4.Medium

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

V_s = 15 VR₁ = 300 ΩR₂ = 1000 ΩR₃ = 10 ΩR₄ = 600 Ω

R_th = Ω

5.Hard

A quarter bridge (one active gauge, GF = 2.05) is excited with 2.5 V. The largest strain to be measured is 200 µε, and it must give 5 V at the input of an analogue-to-digital converter. Find the amplifier gain G.

V_s = 2.5 VGF = 2.05ε_max = 200 µεV_FS = 5 V

G =

6.Hard

A quarter bridge (one active gauge, GF = 2.1) is excited with 10 V. The largest strain to be measured is 1200 µε, and it must give 2.5 V at the input of an analogue-to-digital converter. Find the amplifier gain G.

V_s = 10 VGF = 2.1ε_max = 1200 µεV_FS = 2.5 V

G =

Answer key

1. V_ab = 0.6471 V
2. V_ab = −9.668 V
3. V_ab = 238.1 mV
4. R_th = 240.6 Ω
5. G = 19512
6. G = 396.8

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