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 bridge shown is supplied with V_s = 3 V and its output is open. Find the current I_s drawn from the supply, in mA.

V_s = 3 VR₁ = 500 ΩR₂ = 40 ΩR₃ = 10 ΩR₄ = 150 Ω

I_s = mA

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 10 Ω, R₂ = 250 Ω and R₄ = 500 Ω. Find the setting R₃.

R₁ = 10 ΩR₂ = 250 ΩR₄ = 500 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 = 15 VR₁ = 1000 ΩR₂ = 300 ΩR₃ = 120 ΩR₄ = 120 Ω

R_th = Ω

4.Medium

A bridge has four 220 Ω arms and V_s = 12 V. The sensor R₂ increases by ΔR = 44 Ω. Find the exact output V_ab in mV.

V_s = 12 VR = 220 ΩΔR = 44 Ω

V_ab = mV

5.Hard

A bridge with 1000 Ω arms is excited with 2.5 V and has one active gauge (quarter bridge). The gauge factor is 2.05 and the strain is 1500 µε. Find the bridge output V_o in mV.

V_s = 2.5 VGF = 2.05ε = 1500 µε

V_o = mV

6.Hard

A bridge with 350 Ω arms is excited with 5 V and has one active gauge (quarter bridge). The gauge factor is 2.1 and the strain is 200 µε. Find the bridge output V_o in mV.

V_s = 5 VGF = 2.1ε = 200 µε

V_o = mV

Answer key

1. I_s = 24.31 mA
2. R₃ = 20 Ω
3. R_th = 290.8 Ω
4. V_ab = 545.5 mV
5. V_o = 1.922 mV
6. V_o = 0.525 mV

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