In a slide-wire (metre) bridge a known 20 Ω resistor sits in the left gap and an unknown resistor Rₓ in the right gap. The galvanometer reads zero when the jockey is 20 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 = 100 Ω, R₂ = 100 Ω and R₃ = 600 Ω. Find the unknown resistor R4.
A 400 Ω strain gauge is one arm (R₂) of a bridge with four equal 400 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 four 150 Ω arms is supplied with 3 V. When the sensor R₂ changes, the output reads Vab = 14.85 mV. Find the exact change ΔR of R₂.
A bridge with 120 Ω arms is excited with 2.5 V and has one active gauge (quarter bridge). The gauge factor is 2 and the strain is 200 µε. Find the bridge output Vo in mV.
A quarter bridge with one active gauge (GF = 2) is excited with 5 V. Under load the output reads 3 mV. Find the strain ε in µε.
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