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

Find the open-circuit output voltage V_ab = V_a − V_b of the bridge shown, with V_s = 15 V.

V_s = 15 VR₁ = 10 ΩR₂ = 400 ΩR₃ = 800 ΩR₄ = 150 Ω

V_ab = V

2.Easy

The Wheatstone bridge in the diagram is balanced by adjusting R₃. R₁ = 800 Ω, R₂ = 40 Ω and R₄ = 120 Ω. Find the setting R₃.

R₁ = 800 ΩR₂ = 40 ΩR₄ = 120 Ω

R₃ = Ω

3.Medium

A 120 Ω strain gauge is one arm (R₂) of a bridge with four equal 120 Ω arms and an excitation of 6 V. Find the power P_g dissipated in the gauge, in mW. Self-heating limits the excitation.

V_s = 6 VR = 120 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 = 9 VR₁ = 250 ΩR₂ = 120 ΩR₃ = 40 ΩR₄ = 80 Ω

R_th = Ω

5.Hard

A bridge with 350 Ω arms is excited with 3 V and has one active gauge (quarter bridge). The gauge factor is 2.1 and the strain is 400 µε. Find the bridge output V_o in mV.

V_s = 3 VGF = 2.1ε = 400 µε

V_o = mV

6.Hard

A bridge with 120 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 500 µε. Find the bridge output V_o in mV.

V_s = 3 VGF = 2ε = 500 µε

V_o = mV

Answer key

1. V_ab = 12.27 V
2. R₃ = 2400 Ω
3. P_g = 75 mW
4. R_th = 107.7 Ω
5. V_o = 0.63 mV
6. V_o = 1.5 mV

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