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 = 12 V.

V_s = 12 VR₁ = 100 ΩR₂ = 1000 ΩR₃ = 10 ΩR₄ = 20 Ω

V_ab = V

2.Easy

The Wheatstone bridge in the diagram is balanced: the galvanometer reads zero. R₁ = 60 Ω, R₂ = 50 Ω and R₃ = 60 Ω. Find the unknown resistor R₄.

R₁ = 60 ΩR₂ = 50 ΩR₃ = 60 Ω

R₄ = Ω

3.Medium

A bridge with four 220 Ω arms is supplied with 10 V. When the sensor R₂ changes, the output reads V_ab = 238.1 mV. Find the exact change ΔR of R₂.

V_s = 10 VR = 220 ΩV_ab = 238.1 mV

ΔR = Ω

4.Medium

A bridge with four 500 Ω arms is supplied with 15 V. When the sensor R₂ changes, the output reads V_ab = 74.26 mV. Find the exact change ΔR of R₂.

V_s = 15 VR = 500 ΩV_ab = 74.26 mV

ΔR = Ω

5.Hard

A load cell (a full bridge of strain gauges) has a rated output of 3 mV/V at its rated load of 100 kg. It is excited with 12 V. Find its output V_o under a load of 40 kg.

3 mV/VF_rated = 100 kgV_s = 12 VF = 40 kg

V_o = mV

6.Hard

A 1000 Ω strain gauge with gauge factor 2.05 is bonded to a steel bar. Under load its resistance rises by 0.5125 Ω. Find the strain ε in microstrain (µε).

R = 1000 ΩGF = 2.05ΔR = 0.5125 Ω

ε = µε

Answer key

1. V_ab = 2.909 V
2. R₄ = 50 Ω
3. ΔR = 22 Ω
4. ΔR = 10 Ω
5. V_o = 14.4 mV
6. ε = 250 µε

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