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 = 10 V.

V_s = 10 VR₁ = 50 ΩR₂ = 10 ΩR₃ = 500 ΩR₄ = 150 Ω

V_ab = V

2.Easy

The bridge shown is supplied with V_s = 12 V and its output is open. Find the current I_s drawn from the supply, in mA.

V_s = 12 VR₁ = 500 ΩR₂ = 800 ΩR₃ = 500 ΩR₄ = 100 Ω

I_s = mA

3.Medium

A bridge has four 100 Ω arms and V_s = 6 V. The sensor R₂ increases by ΔR = 10 Ω. Find the exact output V_ab in mV.

V_s = 6 VR = 100 ΩΔR = 10 Ω

V_ab = mV

4.Medium

A bridge has four 220 Ω arms and V_s = 10 V. The sensor R₂ increases by ΔR = 44 Ω. Find the exact output V_ab in mV.

V_s = 10 VR = 220 ΩΔR = 44 Ω

V_ab = mV

5.Hard

A bridge with 350 Ω arms is excited with 3 V and has two active gauges in adjacent arms, one in tension and one in compression (half bridge). The gauge factor is 2.1 and the strain is 1200 µε. Find the bridge output V_o in mV.

V_s = 3 VGF = 2.1ε = 1200 µε

V_o = mV

6.Hard

A load cell (a full bridge of strain gauges) has a rated output of 2 mV/V at its rated load of 1000 kg. It is excited with 5 V. Find its output V_o under a load of 600 kg.

2 mV/VF_rated = 1000 kgV_s = 5 VF = 600 kg

V_o = mV

Answer key

1. V_ab = −0.641 V
2. I_s = 29.23 mA
3. V_ab = 142.9 mV
4. V_ab = 454.5 mV
5. V_o = 3.78 mV
6. V_o = 6 mV

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