Editing Wheatstone bridge (section)

{{Short description|System to measure electrical resistance}}
{{More citations needed|date=March 2019}}

[[Image:Wheatstonebridge.svg|thumb|300px|alt=A Wheatstone bridge has four resistors forming the sides of a diamond shape. A battery is connected across one pair of opposite corners, and a galvanometer across the other pair. |Wheatstone bridge [[circuit diagram]]. The unknown resistance ''R''<sub>''x''</sub> is to be measured; resistances ''R''<sub>1</sub>, ''R''<sub>2</sub> and ''R''<sub>3</sub> are known, where ''R''<sub>2</sub> is adjustable. When the measured voltage ''V''<sub>''G''</sub> is 0, both legs have equal voltage ratios: ''R''<sub>2</sub>/''R''<sub>1</sub> =&nbsp;''R''<sub>''x''</sub>/''R''<sub>3</sub> and ''R''<sub>''x''</sub>=&nbsp;''R''<sub>3</sub>''R''<sub>2</sub>/''R''<sub>1</sub>.]]

A '''Wheatstone bridge''' is an [[electrical circuit]] used to measure an unknown [[electrical resistance]] by balancing two legs of a [[bridge circuit]], one leg of which includes the unknown component. The primary benefit of the circuit is its ability to provide extremely accurate measurements (in contrast with something like a simple [[voltage divider]]).<ref>"Circuits in Practice: The Wheatstone Bridge, What It Does, and Why It Matters", as discussed in this MIT ES.333 class [https://www.youtube.com/watch?v=-G-dySnSSG4 video]</ref> Its operation is similar to the original [[Potentiometer (measuring instrument)|potentiometer]].

The Wheatstone bridge was invented by [[Samuel Hunter Christie]] (sometimes spelled "Christy") in 1833 and improved and popularized by Sir [[Charles Wheatstone]] in 1843.<ref>{{cite journal |last=Wheatstone |first=Charles |date=1843 |title=XIII. The Bakerian lecture.—An account of several new instruments and processes for determining the constants of a voltaic circuit |journal=Phil. Trans. R. Soc. |volume=133 |pages=303–327 |doi=10.1098/rstl.1843.0014}}</ref>  One of the Wheatstone bridge's initial uses was for [[soil analysis]] and comparison.<ref>{{cite journal |title=The Genesis of the Wheatstone Bridge |first=Stig |last=Ekelof |journal=Engineering Science and Education Journal |volume=10 |issue=1 |date=February 2001 |pages=37–40 |doi=10.1049/esej:20010106  |doi-broken-date=7 December 2024 |url=https://edisciplinas.usp.br/pluginfile.php/5618117/mod_resource/content/1/The%20genesis%20of%20Wheatstone%20bridge.pdf}} discusses [[Samuel Hunter Christie|Christie's]] and [[Charles Wheatstone|Wheatstone]]'s contributions, and why the bridge carries Wheatstone's name.</ref>