Enter your Input Voltage (Vin), known resistances R1, R2, and R3, and an Unknown Resistance (Rx) to calculate the Bridge Voltage (VB), check Bridge Balance, and compare your Left Arm Ratio to your Right Arm Ratio — the Wheatstone Bridge Calculator also back-calculates Rx when the bridge is balanced.
Bridge Voltage (VB)
--
Calculated Rx
--
Bridge Balance
--
Left Arm Ratio
--
Right Arm Ratio
--
A Wheatstone bridge is an electrical circuit used to measure unknown resistance values. It consists of four resistors arranged in a diamond pattern with a voltage source and a detector between opposite corners.
For a balanced bridge, use the formula: Rx = (R2 × R3) / R1. When the bridge is balanced, the voltage across the detector is zero, and this relationship holds true.
The principle is based on voltage division. When the ratio R1/R2 equals R3/Rx, the bridge is balanced and no current flows through the detector, making the bridge voltage zero.
Wheatstone bridges are used in strain gauges, pressure sensors, temperature sensors, and precision resistance measurements. They're ideal for detecting small changes in resistance values.
In a perfectly balanced Wheatstone bridge, the output current through the detector is zero because there's no voltage difference between the two middle points of the bridge.
Connect the unknown resistor as Rx, adjust known resistors until the bridge balances (detector reads zero), then calculate Rx using the balance equation. This method provides high accuracy.