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Wheatstone Bridge Calculator

Calculate Wheatstone bridge output voltage, balance condition, and sensitivity. Used for strain gauges, RTDs, and precision resistance measurements.

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Formula

Vout=Vin(R3R1+R3−R4R2+R4)V_{out} = V_{in} \left(\frac{R_3}{R_1+R_3} - \frac{R_4}{R_2+R_4}\right)
V_out — Differential output voltage (V)
V_in — Bridge supply voltage (V)
R1–R4 — Bridge arm resistances (Ω)

How It Works

A Wheatstone bridge is a precision electrical circuit used for measuring unknown electrical resistances by comparing them to known reference resistances. The circuit consists of four resistors arranged in a diamond-like configuration, with a voltage source across two diagonal points and a sensitive voltmeter measuring the voltage difference across the other two points. When the bridge is balanced, the output voltage becomes zero, allowing precise resistance measurements.

Worked Example

Problem: Calculate the output voltage for a Wheatstone bridge with Vin = 5V, R1 = 100Ω, R2 = 120Ω, R3 = 110Ω, R4 = 130Ω Solution: 1. Apply Vout = Vin·(R3/(R1+R3) - R4/(R2+R4)) 2. Vout = 5 · (110/(100+110) - 130/(120+130)) 3. Vout = 5 · (0.524 - 0.521) 4. Vout = 5 · 0.003 5. Vout = 0.015V or 15mV

Practical Tips

  • ✓Calibrate the bridge regularly for accurate measurements
  • ✓Use high-precision resistors for sensitive measurements
  • ✓Minimize external electrical noise in the measurement setup

Common Mistakes

  • ✗Misinterpreting bridge balance conditions
  • ✗Ignoring temperature effects on resistances
  • ✗Using inappropriate precision measurement equipment

Frequently Asked Questions

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