In a slide-wire (metre) bridge a known 50 Ω resistor sits in the left gap and an unknown resistor Rₓ in the right gap. The galvanometer reads zero when the jockey is 40 cm from the left end A of the 100 cm wire. Find Rx.
The Wheatstone bridge in the diagram is balanced: the galvanometer reads zero. R₁ = 300 Ω, R₂ = 250 Ω and R₃ = 300 Ω. Find the unknown resistor R4.
A bridge has four 200 Ω arms and Vs = 10 V. The sensor R₂ increases by ΔR = 16 Ω. Find the exact output Vab in mV.
A 1000 Ω strain gauge is one arm (R₂) of a bridge with four equal 1000 Ω arms and an excitation of 5 V. Find the power Pg dissipated in the gauge, in mW. Self-heating limits the excitation.
A bridge with 120 Ω arms is excited with 10 V and has four active gauges, two in tension and two in compression (full bridge). The gauge factor is 2 and the strain is 750 µε. Find the bridge output Vo in mV.
A strain gauge (GF = 2) on a member with E = 210 GPa forms a quarter bridge excited with 2.5 V. The output reads 0.313 mV. Find the axial stress σ in MPa.
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