In a slide-wire (metre) bridge a known 10 Ω resistor sits in the left gap and an unknown resistor Rₓ in the right gap. The galvanometer reads zero when the jockey is 25 cm from the left end A of the 100 cm wire. Find Rx.
The bridge shown is supplied with Vs = 2 V and its output is open. Find the current Is drawn from the supply, in mA.
A 500 Ω strain gauge is one arm (R₂) of a bridge with four equal 500 Ω arms and an excitation of 2 V. Find the power Pg dissipated in the gauge, in mW. Self-heating limits the excitation.
A bridge has four 120 Ω arms and Vs = 10 V. The sensor R₂ increases by ΔR = 0.96 Ω. Using the small-change approximation, find the output Vab in mV.
A quarter bridge (one active gauge, GF = 2.1) is excited with 5 V. The largest strain to be measured is 1200 µε, and it must give 10 V at the input of an analogue-to-digital converter. Find the amplifier gain G.
A quarter bridge (one active gauge, GF = 2.05) is excited with 2.5 V. The largest strain to be measured is 250 µε, and it must give 10 V at the input of an analogue-to-digital converter. Find the amplifier gain G.
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