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.

New worksheet Practise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________ Date: ____________

1.Easy

Find the open-circuit output voltage V_ab = V_a − V_b of the bridge shown, with V_s = 5 V.

V_s = 5 VR₁ = 150 ΩR₂ = 250 ΩR₃ = 120 ΩR₄ = 1000 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 = 12 V.

V_s = 12 VR₁ = 150 ΩR₂ = 400 ΩR₃ = 20 ΩR₄ = 250 Ω

V_ab = V

3.Medium

A bridge has four 120 Ω arms and V_s = 3 V. The sensor R₂ increases by ΔR = 1.2 Ω. Using the small-change approximation, find the output V_ab in mV.

V_s = 3 VR = 120 ΩΔR = 1.2 Ω

V_ab = mV

4.Medium

A galvanometer with a resistance of 100 Ω is connected between a and b of the bridge shown (V_s = 6 V). Find the galvanometer current I_g from a to b, in µA.

V_s = 6 VR₁ = 120 ΩR₂ = 800 ΩR₃ = 10 ΩR₄ = 40 ΩR_g = 100 Ω

I_g = µA

5.Hard

A load cell (a full bridge of strain gauges) has a rated output of 1.5 mV/V at its rated load of 100 kg. It is excited with 10 V. Find its output V_o under a load of 40 kg.

1.5 mV/VF_rated = 100 kgV_s = 10 VF = 40 kg

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 500 kg. It is excited with 5 V. Find its output V_o under a load of 400 kg.

2 mV/VF_rated = 500 kgV_s = 5 VF = 400 kg

V_o = mV

Answer key

1. V_ab = −1.339 V
2. V_ab = −2.384 V
3. V_ab = 7.5 mV
4. I_g = 1966 µA
5. V_o = 6 mV
6. V_o = 8 mV

Full step-by-step solutions: practise this topic on examproblems.com.