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 = 6 V.

V_s = 6 VR₁ = 200 ΩR₂ = 400 ΩR₃ = 10 ΩR₄ = 500 Ω

V_ab = V

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 10 Ω, R₂ = 100 Ω and R₄ = 500 Ω. Find the setting R₃.

R₁ = 10 ΩR₂ = 100 ΩR₄ = 500 Ω

R₃ = Ω

3.Medium

A galvanometer with a resistance of 20 Ω is connected between a and b of the bridge shown (V_s = 12 V). Find the galvanometer current I_g from a to b, in µA.

V_s = 12 VR₁ = 150 ΩR₂ = 600 ΩR₃ = 120 ΩR₄ = 40 ΩR_g = 20 Ω

I_g = µA

4.Medium

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

V_s = 15 VR₁ = 200 ΩR₂ = 500 ΩR₃ = 150 ΩR₄ = 40 Ω

R_th = Ω

5.Hard

A bridge with 1000 Ω arms is excited with 2.5 V and has four active gauges, two in tension and two in compression (full bridge). The gauge factor is 2.1 and the strain is 750 µε. Find the bridge output V_o in mV.

V_s = 2.5 VGF = 2.1ε = 750 µε

V_o = mV

6.Hard

A bridge with 350 Ω arms is excited with 3 V and has four active gauges, two in tension and two in compression (full bridge). The gauge factor is 2.1 and the strain is 750 µε. Find the bridge output V_o in mV.

V_s = 3 VGF = 2.1ε = 750 µε

V_o = mV

Answer key

1. V_ab = −1.882 V
2. R₃ = 50 Ω
3. I_g = 38824 µA
4. R_th = 174.4 Ω
5. V_o = 3.938 mV
6. V_o = 4.725 mV

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