Wheatstone bridge calculator

Calculate bridge output, arm voltages and the resistance required for balance.

Schematic

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Results

Differential output-119.05 mV

Bridge output versus R4

Output

Left midpoint	2.5 V
Right midpoint	2.62 V
R4 for balance	1 kΩ

Advanced results

Excitation current	4.88 mA
Output resistance	1.02 kΩ

How wheatstone bridge works

Two voltage dividers share one excitation source. The differential output is the left midpoint voltage minus the right midpoint voltage. The bridge balances when the resistance ratios match. The output is unloaded in this example.

V_{out}=V_1\left(\frac{R_2}{R_1+R_2}-\frac{R_4}{R_3+R_4}\right)

Ideal resistors and an ideal excitation source. No measuring-instrument load, lead resistance or temperature effects are included.

Change the form inputs or click a component value on the schematic. Choose Try in CircuitSim to simulate the configured circuit.

Do the math

Selected input values
R1	1 kΩ
R2	1 kΩ
R3	1 kΩ
R4	1.1 kΩ
V1	5 V

Left midpoint: $V_L=V_1R_2/(R_1+R_2)$
$5\,\mathrm{V}\times\frac{1\,\mathrm{k\Omega}}{2\,\mathrm{k\Omega}}$
≈ 2.5 V
Right midpoint: $V_R=V_1R_4/(R_3+R_4)$
$5\,\mathrm{V}\times\frac{1.1\,\mathrm{k\Omega}}{2.1\,\mathrm{k\Omega}}$
≈ 2.62 V
Bridge output: $V_{out}=V_L-V_R$
$2.5\,\mathrm{V}-2.62\,\mathrm{V}$
≈ -119.05 mV
Balance resistance: $R_{4,balanced}=R_2R_3/R_1$
$\frac{1\,\mathrm{k\Omega}\times1\,\mathrm{k\Omega}}{1\,\mathrm{k\Omega}}$
≈ 1 kΩ

Wheatstone bridge calculator

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Schematic

Results

How wheatstone bridge works

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