Wheatstone Bridge
Differential output of the four-arm bridge — the front end of half of all sensors.
Your recent runs (stored only in your browser)
No calculations yet — results land here so you can compare runs.
The engineering
Two dividers back to back: the bridge converts a tiny resistance change into a differential voltage riding on a common mode of Vex/2 — which is exactly what instrumentation amplifiers were born to reject.
The mV/V row is how load cells are specified: a 2 mV/V cell at 10 V excitation gives 20 mV at full scale.
Where this math comes from
Samuel Hunter Christie invented the circuit in 1833, but it was Charles Wheatstone's 1843 Bakerian Lecture that showed the world what the 'differential resistance measurer' could do — and Wheatstone, to his credit, always named Christie. The null method let Victorian engineers measure resistance with a galvanometer that only had to detect zero.
William Thomson (Lord Kelvin) pushed it to low resistances with his 1861 double bridge, and the strain-gauge era of the 1930s turned Christie's curiosity into the front end of nearly every force, pressure, and torque measurement made since.
- 1833Samuel Hunter ChristieInvents the four-arm bridge circuit.
- 1843Charles WheatstoneBakerian Lecture popularizes the bridge (crediting Christie).
- 1861Lord KelvinDouble bridge extends null measurement to milliohms.
- 1938Simmons & RugeBonded strain gauge makes the bridge the universal sensor front end.
See the full timeline of the math behind every calculator →
Runs entirely in your browser — nothing you enter leaves this page. Your recent runs are stored only on your device.