Wheatstone Bridge Calculator Formula

Understand the math behind the wheatstone bridge calculator. Each variable explained with a worked example.

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Formulas Used

Bridge Voltage

bridge_voltage = v_supply * (r3/(r1+r3) - r4/(r2+r4))

Ratio R1/R3

ratio_left = r1/r3

Ratio R2/R4

ratio_right = r2/r4

Variables

VariableDescriptionDefault
v_supplySupply Voltage(V)10
r1R1 (top-left)(Ω)1000
r2R2 (top-right)(Ω)2000
r3R3 (bottom-left)(Ω)1000
r4R4 (bottom-right)(Ω)2000

How It Works

Wheatstone Bridge Analysis

A Wheatstone bridge measures unknown resistance by balancing two divider legs.

Formula

V_bridge = V_s x [R3/(R1+R3) - R4/(R2+R4)]

Balanced when R1/R3 = R2/R4 (bridge voltage = 0).

Worked Example

10 V supply, R1=R3=1k, R2=R4=2k.

v_supply = 10r1 = 1000r2 = 2000r3 = 1000r4 = 2000
  1. 01Left: R3/(R1+R3) = 1000/2000 = 0.5
  2. 02Right: R4/(R2+R4) = 2000/4000 = 0.5
  3. 03V_bridge = 10 x (0.5 - 0.5) = 0 V (balanced)

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