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

In the bridge shown, V_s = 9 V, R₁ = 800 Ω and R₂ = 50 Ω. Find the voltage V_a of node a with respect to the negative supply rail.

V_s = 9 VR₁ = 800 ΩR₂ = 50 ΩR₃ = 80 ΩR₄ = 100 Ω

V_a = V

2.Easy

The Wheatstone bridge in the diagram is balanced: the galvanometer reads zero. R₁ = 50 Ω, R₂ = 50 Ω and R₃ = 10 Ω. Find the unknown resistor R₄.

R₁ = 50 ΩR₂ = 50 ΩR₃ = 10 Ω

R₄ = Ω

3.Medium

A galvanometer with a resistance of 100 Ω is connected between a and b of the bridge shown (V_s = 10 V). Find the galvanometer current I_g from a to b, in µA.

V_s = 10 VR₁ = 400 ΩR₂ = 150 ΩR₃ = 60 ΩR₄ = 100 ΩR_g = 100 Ω

I_g = µA

4.Medium

A bridge with four 400 Ω arms is supplied with 5 V. When the sensor R₂ changes, the output reads V_ab = 119 mV. Find the exact change ΔR of R₂.

V_s = 5 VR = 400 ΩV_ab = 119 mV

ΔR = Ω

5.Hard

A bridge with 350 Ω arms is excited with 2.5 V and has one active gauge (quarter bridge). The gauge factor is 2 and the strain is 400 µε. Find the bridge output V_o in mV.

V_s = 2.5 VGF = 2ε = 400 µε

V_o = mV

6.Hard

A quarter bridge (one active gauge, GF = 2) is excited with 5 V. The largest strain to be measured is 500 µε, and it must give 3.3 V at the input of an analogue-to-digital converter. Find the amplifier gain G.

V_s = 5 VGF = 2ε_max = 500 µεV_FS = 3.3 V

G =

Answer key

1. V_a = 0.5294 V
2. R₄ = 10 Ω
3. I_g = −14286 µA
4. ΔR = 40 Ω
5. V_o = 0.5 mV
6. G = 2640

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