Wheatstone Bridge Calculator
With equal 1 kΩ ratio arms, a bridge balanced at R₃ = 470 Ω shows the unknown is 470 Ω.
470 Ω
- Ratio R₂/R₁
- 1
Step-by-step solution
- At balance R₁/R₂ = R₃/Rₓ
- Rₓ = R₃ × R₂ ÷ R₁ = 470 × 1000 ÷ 1000 = 470 Ω
Wheatstone Bridge Formula
Rₓ = R₂R₃ / R₁ at balance
Vₒᵤₜ = V_s [R₂/(R₁ + R₂) − Rₓ/(R₃ + Rₓ)]
Worked Example
A bridge with equal 1 kΩ ratio arms balanced with R₃ = 470 Ω:
- At balance R₁/R₂ = R₃/Rₓ
- Rₓ = R₃ × R₂ ÷ R₁ = 470 × 1000 ÷ 1000 = 470 Ω
GATE tip
Bridge sensitivity is greatest when all four arms are equal. For small changes ΔR in one arm of an equal-arm bridge, Vₒᵤₜ ≈ V_s ΔR/(4R), the basis of the quarter-bridge strain gauge.
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Example: A = 100 ± 1 and B = 20 ± 0.4 multiplied, limiting errors: Result y = 2000 ± 60.
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Ammeter Shunt Calculator
R_sh = I_m R_m / (I − I_m), R_s = V/I_m − R_m
multiplying power m = I/I_m, so R_sh = R_m/(m − 1)
Example: A 1 mA, 100 Ω meter extended to read 1 A: Shunt resistance R_sh = 0.1001 Ω.
Frequently asked questions
Why is a bridge so precise?
At balance no current flows in the detector, so the result depends only on resistor ratios, not on the supply voltage or the detector’s calibration.
When is a Kelvin bridge used?
For resistances below about 1 Ω, where lead and contact resistances would swamp a Wheatstone bridge.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Wheatstone Bridge Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/wheatstone-bridge-calculator/
IEEE
Scientific Converters, "Wheatstone Bridge Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/wheatstone-bridge-calculator/