Work out wheatstone bridge instantly with clear inputs, formula shown and shareable results.
A Wheatstone bridge balances when R1/R2 = R3/R4, so the unknown arm equals R2 x R3 / R1. Away from balance the output is the difference between two voltage dividers, which is why the bridge is the standard front end for strain gauges and resistance thermometers: it converts a tiny fractional resistance change into a differential voltage.
Wheatstone bridge
At balance R1 x R4 = R2 x R3, so Rx = R2 x R3 / R1
Electrical results are planning estimates only. Verify against the applicable wiring rules (IEC 60364, BS 7671, NEC or local code) and have all installation work designed and checked by a qualified electrician.
The bridge output is zero at balance, so the small change of interest is measured against zero rather than as a tiny fraction of a large reading. That removes offset and gain error.
Excitation voltage, which is capped by self-heating of the sensing element, and the noise and drift of the instrumentation amplifier that follows.