Physics

Wheatstone Bridge Calculator

Find the unknown resistance in a balanced Wheatstone bridge.

Calculated Output

Unknown resistance Rₓ (Ω) 300

Formula: Rₓ = R₂·R₃ ÷ R₁

Step-by-Step Breakdown

1. Values used:

2. R₁ = 100 Ω

3. R₂ = 200 Ω

4. R₃ = 150 Ω

6. Unknown resistance Rₓ = R₁ + R₂ = 100 + 200 = 300Ω

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The math behind it

At balance (no galvanometer current), R₁/R₂ = R₃/Rₓ, so Rₓ = R₂·R₃ ÷ R₁.

R₁ = 100, R₂ = 200, R₃ = 150 → Rₓ = 300 Ω.

What does 'balanced' mean?

The bridge output voltage is zero, so the ratios are equal.