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

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 120 Ω, R₂ = 20 Ω and R₄ = 600 Ω. Find the setting R₃.

R₁ = 120 ΩR₂ = 20 ΩR₄ = 600 Ω

R₃ = Ω

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 = 250 ΩR₂ = 40 ΩR₃ = 40 ΩR₄ = 1000 Ω

I_s = mA

3.Medium

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

V_s = 3 VR₁ = 10 ΩR₂ = 600 ΩR₃ = 200 ΩR₄ = 50 Ω

R_th = Ω

4.Medium

A bridge with four 100 Ω arms is supplied with 10 V. When the sensor R₂ changes, the output reads V_ab = 283 mV. Find the exact change ΔR of R₂.

V_s = 10 VR = 100 ΩV_ab = 283 mV

ΔR = Ω

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 1000 kg. It is excited with 5 V. Find its output V_o under a load of 250 kg.

1.5 mV/VF_rated = 1000 kgV_s = 5 VF = 250 kg

V_o = mV

6.Hard

A bridge with 350 Ω arms is excited with 10 V and has one active gauge (quarter bridge). The gauge factor is 2.05 and the strain is 1000 µε. Find the bridge output V_o in mV.

V_s = 10 VGF = 2.05ε = 1000 µε

V_o = mV

Answer key

1. R₃ = 3600 Ω
2. I_s = 52.92 mA
3. R_th = 49.84 Ω
4. ΔR = 12 Ω
5. V_o = 1.875 mV
6. V_o = 5.125 mV

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