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

In the bridge shown, V_s = 9 V, R₁ = 100 Ω and R₂ = 600 Ω. Find the voltage V_a of node a with respect to the negative supply rail.

V_s = 9 VR₁ = 100 ΩR₂ = 600 ΩR₃ = 10 ΩR₄ = 40 Ω

V_a = V

2.Easy

The Wheatstone bridge in the diagram is balanced: the galvanometer reads zero. R₁ = 1000 Ω, R₂ = 500 Ω and R₃ = 20 Ω. Find the unknown resistor R₄.

R₁ = 1000 ΩR₂ = 500 ΩR₃ = 20 Ω

R₄ = Ω

3.Medium

A bridge has four 250 Ω arms and V_s = 2 V. The sensor R₂ increases by ΔR = 25 Ω. Find the exact output V_ab in mV.

V_s = 2 VR = 250 ΩΔR = 25 Ω

V_ab = mV

4.Medium

A bridge has four 250 Ω arms and V_s = 15 V. The sensor R₂ increases by ΔR = 50 Ω. Find the exact output V_ab in mV.

V_s = 15 VR = 250 ΩΔR = 50 Ω

V_ab = mV

5.Hard

A bridge with 120 Ω arms is excited with 2.5 V and has two active gauges in adjacent arms, one in tension and one in compression (half bridge). The gauge factor is 2 and the strain is 200 µε. Find the bridge output V_o in mV.

V_s = 2.5 VGF = 2ε = 200 µε

V_o = mV

6.Hard

A bridge with 350 Ω arms is excited with 10 V and has one active gauge (quarter bridge). The gauge factor is 2 and the strain is 200 µε. Find the bridge output V_o in mV.

V_s = 10 VGF = 2ε = 200 µε

V_o = mV

Answer key

1. V_a = 7.714 V
2. R₄ = 10 Ω
3. V_ab = 47.62 mV
4. V_ab = 681.8 mV
5. V_o = 0.5 mV
6. V_o = 1 mV

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