Calculate the unknown resistance in a Wheatstone bridge circuit when balanced.
Resistor Values
Ω
Ω
Ω
Calculation Results
Enter the three known resistor values
Quick Reference
R1, R2Ratio arm resistors
R3Standard arm resistor
RxUnknown resistor
Overview
A Wheatstone bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit. It is extremely accurate for measuring small resistance changes.
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Pro Tips
Rx = (R2 / R1) × R3 for a balanced bridge.
Balanced means the voltage difference between the two midpoints is zero.
Commonly used with strain gauges and temperature sensors.
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Fun Facts
"The circuit was invented by Samuel Hunter Christie in 1833 but improved and popularized by Sir Charles Wheatstone in 1843."
"It can measure changes in resistance as small as one part in a million."
"Strain gauges used in weighing scales often use Wheatstone bridges."
