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

In the bridge shown, V_s = 3 V, R₁ = 800 Ω and R₂ = 1000 Ω. Find the voltage V_a of node a with respect to the negative supply rail.

V_s = 3 VR₁ = 800 ΩR₂ = 1000 ΩR₃ = 150 ΩR₄ = 10 Ω

V_a = V

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 400 Ω, R₂ = 400 Ω and R₄ = 150 Ω. Find the setting R₃.

R₁ = 400 ΩR₂ = 400 ΩR₄ = 150 Ω

R₃ = Ω

3.Medium

A bridge has four 300 Ω arms and V_s = 12 V. The sensor R₂ increases by ΔR = 45 Ω. Find the exact output V_ab in mV.

V_s = 12 VR = 300 ΩΔR = 45 Ω

V_ab = mV

4.Medium

A bridge has four 220 Ω arms and V_s = 9 V. The sensor R₂ increases by ΔR = 1.1 Ω. Using the small-change approximation, find the output V_ab in mV.

V_s = 9 VR = 220 ΩΔR = 1.1 Ω

V_ab = mV

5.Hard

A load cell (a full bridge of strain gauges) has a rated output of 1 mV/V at its rated load of 500 kg. It is excited with 12 V. Find its output V_o under a load of 300 kg.

1 mV/VF_rated = 500 kgV_s = 12 VF = 300 kg

V_o = mV

6.Hard

A bridge with 1000 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 2.05 and the strain is 600 µε. Find the bridge output V_o in mV.

V_s = 3 VGF = 2.05ε = 600 µε

V_o = mV

Answer key

1. V_a = 1.667 V
2. R₃ = 150 Ω
3. V_ab = 418.6 mV
4. V_ab = 11.25 mV
5. V_o = 7.2 mV
6. V_o = 3.69 mV

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