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 Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 600 Ω, R₂ = 20 Ω and R₄ = 150 Ω. Find the setting R₃.

R₁ = 600 ΩR₂ = 20 ΩR₄ = 150 Ω

R₃ = Ω

2.Easy

In the bridge shown, V_s = 10 V, R₁ = 500 Ω and R₂ = 400 Ω. Find the voltage V_a of node a with respect to the negative supply rail.

V_s = 10 VR₁ = 500 ΩR₂ = 400 ΩR₃ = 120 ΩR₄ = 800 Ω

V_a = V

3.Medium

A 470 Ω strain gauge is one arm (R₂) of a bridge with four equal 470 Ω arms and an excitation of 5 V. Find the power P_g dissipated in the gauge, in mW. Self-heating limits the excitation.

V_s = 5 VR = 470 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 = 10 VR₁ = 600 ΩR₂ = 500 ΩR₃ = 800 ΩR₄ = 800 Ω

R_th = Ω

5.Hard

A bridge with 1000 Ω arms is excited with 3 V and has one active gauge (quarter bridge). The gauge factor is 2.05 and the strain is 200 µε. Find the bridge output V_o in mV.

V_s = 3 VGF = 2.05ε = 200 µε

V_o = mV

6.Hard

A bridge with 350 Ω arms is excited with 3 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 = 3 VGF = 2ε = 200 µε

V_o = mV

Answer key

1. R₃ = 4500 Ω
2. V_a = 4.444 V
3. P_g = 13.3 mW
4. R_th = 672.7 Ω
5. V_o = 0.3075 mV
6. V_o = 0.6 mV

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