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 bridge shown is supplied with V_s = 9 V and its output is open. Find the current I_s drawn from the supply, in mA.

V_s = 9 VR₁ = 400 ΩR₂ = 500 ΩR₃ = 500 ΩR₄ = 10 Ω

I_s = mA

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 40 Ω, R₂ = 50 Ω and R₄ = 600 Ω. Find the setting R₃.

R₁ = 40 ΩR₂ = 50 ΩR₄ = 600 Ω

R₃ = Ω

3.Medium

A 1000 Ω strain gauge is one arm (R₂) of a bridge with four equal 1000 Ω arms and an excitation of 2 V. Find the power P_g dissipated in the gauge, in mW. Self-heating limits the excitation.

V_s = 2 VR = 1000 Ω

P_g = mW

4.Medium

A galvanometer with a resistance of 20 Ω is connected between a and b of the bridge shown (V_s = 12 V). Find the galvanometer current I_g from a to b, in µA.

V_s = 12 VR₁ = 120 ΩR₂ = 1000 ΩR₃ = 20 ΩR₄ = 100 ΩR_g = 20 Ω

I_g = µA

5.Hard

A bridge with 120 Ω arms is excited with 10 V and has one active gauge (quarter bridge). The gauge factor is 2 and the strain is 1200 µε. Find the bridge output V_o in mV.

V_s = 10 VGF = 2ε = 1200 µε

V_o = mV

6.Hard

A 120 Ω strain gauge with gauge factor 2.1 is bonded to a steel bar. Under load its resistance rises by 0.0504 Ω. Find the strain ε in microstrain (µε).

R = 120 ΩGF = 2.1ΔR = 0.0504 Ω

ε = µε

Answer key

1. I_s = 27.65 mA
2. R₃ = 480 Ω
3. P_g = 1 mW
4. I_g = 4967 µA
5. V_o = 6 mV
6. ε = 200 µε

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