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 = 10 Ω, R₂ = 80 Ω and R₄ = 800 Ω. Find the setting R₃.

R₁ = 10 ΩR₂ = 80 ΩR₄ = 800 Ω

R₃ = Ω

2.Easy

In a slide-wire (metre) bridge a known 10 Ω resistor sits in the left gap and an unknown resistor Rₓ in the right gap. The galvanometer reads zero when the jockey is 75 cm from the left end A of the 100 cm wire. Find R_x.

R = 10 Ωl = 75 cmL = 100 cm

R_x = Ω

3.Medium

A 400 Ω strain gauge is one arm (R₂) of a bridge with four equal 400 Ω arms and an excitation of 6 V. Find the power P_g dissipated in the gauge, in mW. Self-heating limits the excitation.

V_s = 6 VR = 400 Ω

P_g = mW

4.Medium

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

V_s = 3 VR₁ = 250 ΩR₂ = 100 ΩR₃ = 40 ΩR₄ = 60 Ω

R_th = Ω

5.Hard

A quarter bridge with one active gauge (GF = 2) is excited with 3 V. Under load the output reads 1.8 mV. Find the strain ε in µε.

V_s = 3 VGF = 2V_o = 1.8 mV

ε = µε

6.Hard

A strain gauge (GF = 2) on a member with E = 110 GPa forms a quarter bridge excited with 3 V. The output reads 0.75 mV. Find the axial stress σ in MPa.

V_s = 3 VGF = 2V_o = 0.75 mVE = 110 GPa

σ = MPa

Answer key

1. R₃ = 100 Ω
2. R_x = 3.333 Ω
3. P_g = 22.5 mW
4. R_th = 95.43 Ω
5. ε = 1200 µε
6. σ = 55 MPa

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