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.

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1.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 = 400 ΩR₂ = 150 ΩR₃ = 100 ΩR₄ = 1000 Ω

I_s = mA

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 120 Ω, R₂ = 500 Ω and R₄ = 200 Ω. Find the setting R₃.

R₁ = 120 ΩR₂ = 500 ΩR₄ = 200 Ω

R₃ = Ω

3.Medium

A bridge with four 300 Ω arms is supplied with 2 V. When the sensor R₂ changes, the output reads V_ab = 4.98 mV. Find the exact change ΔR of R₂.

V_s = 2 VR = 300 ΩV_ab = 4.98 mV

ΔR = Ω

4.Medium

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

V_s = 5 VR₁ = 1000 ΩR₂ = 60 ΩR₃ = 50 ΩR₄ = 250 Ω

R_th = Ω

5.Hard

A load cell (a full bridge of strain gauges) has a rated output of 2.5 mV/V at its rated load of 1000 kg. It is excited with 5 V. Find its output V_o under a load of 600 kg.

2.5 mV/VF_rated = 1000 kgV_s = 5 VF = 600 kg

V_o = mV

6.Hard

A load cell (a full bridge of strain gauges) has a rated output of 2.5 mV/V at its rated load of 200 kg. It is excited with 10 V. Find its output V_o under a load of 160 kg.

2.5 mV/VF_rated = 200 kgV_s = 10 VF = 160 kg

V_o = mV

Answer key

1. I_s = 32.73 mA
2. R₃ = 48 Ω
3. ΔR = 3.003 Ω
4. R_th = 98.27 Ω
5. V_o = 7.5 mV
6. V_o = 20 mV

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