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Physics

Wheatstone Bridge Calculator

Unknown resistor Rx = R3 × R2 / R1. Free online Wheatstone Bridge Calculator for physics — instant, accurate results, mobile-friendly, no signup needed.

Rx (Ω)
300

Derivation

  1. ├── 01GivenR1 = 100, R2 = 200, R3 = 150
  2. ├── 02Formulae.R3 × a / t
  3. ├── 03Substitutee.150 × a / t
  4. └── 04Compute Rx (Ω)300
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§01What is

Understanding the Wheatstone Bridge Calculator

The Wheatstone Bridge Calculator computes Rx (Ω) from 3 inputs: r1 (ω), r2 (ω), r3 (ω). Unknown resistor Rx = R3 × R2 / R1.

Physics is the toolkit for turning a real-world observation into a prediction. Whether it’s a falling object, a moving car, or a stressed beam, the equations here are the same ones every engineer relies on. The Wheatstone Bridge Calculator sits in that toolkit — it unknown resistor Rx = R3 × R2 / R1. Enter your numbers above and the result updates instantly; every step of the math is shown in the Derivation panel so you can see exactly how the answer was reached.

§02The Formula

How it’s calculated

e.R3 × a / t

Where

R1
R1 (Ω)
R2
R2 (Ω)
R3
R3 (Ω)
§03Practical Example

Step-by-step walkthrough

Scenario

Apply the formula to a realistic set of inputs: R1 (Ω) = 100, R2 (Ω) = 200, R3 (Ω) = 150.

  1. 01Start by noting the input — R1 (Ω): 100.
  2. 02Start by noting the input — R2 (Ω): 200.
  3. 03Start by noting the input — R3 (Ω): 150.
  4. 04Substitute these values into the formula: e.R3 × a / t
  5. 05Compute Rx (Ω): the calculator returns 300.
  6. 06Cross-check the answer by opening the Derivation panel above — every line of math is shown so you can follow the computation end-to-end.
§04Variants

Common Wheatstone Bridge Problems

The formula gets rearranged depending on which variable you need. Here are the patterns you’ll run into in the real world — find the one that matches your problem and follow the worked steps.

01 · PATTERN

R1 (Ω) halved

R1 = 50 (from 100)

Keep every other input at its default and halve the r1 (ω). See how rx (ω) responds.

  1. 01New R1 (Ω): 50
  2. 02Baseline Rx (Ω): 300
  3. 03New Rx (Ω): 600
  4. 04Rx (Ω) increases by 100% → use this sensitivity to plan for real-world variation.
02 · PATTERN

R1 (Ω) doubled

R1 = 200 (from 100)

Keep every other input at its default and double the r1 (ω). See how rx (ω) responds.

  1. 01New R1 (Ω): 200
  2. 02Baseline Rx (Ω): 300
  3. 03New Rx (Ω): 150
  4. 04Rx (Ω) decreases by 50% → use this sensitivity to plan for real-world variation.
03 · PATTERN

R2 (Ω) halved

R2 = 100 (from 200)

Keep every other input at its default and halve the r2 (ω). See how rx (ω) responds.

  1. 01New R2 (Ω): 100
  2. 02Baseline Rx (Ω): 300
  3. 03New Rx (Ω): 150
  4. 04Rx (Ω) decreases by 50% → use this sensitivity to plan for real-world variation.
04 · PATTERN

R2 (Ω) doubled

R2 = 400 (from 200)

Keep every other input at its default and double the r2 (ω). See how rx (ω) responds.

  1. 01New R2 (Ω): 400
  2. 02Baseline Rx (Ω): 300
  3. 03New Rx (Ω): 600
  4. 04Rx (Ω) increases by 100% → use this sensitivity to plan for real-world variation.
§05FAQ

Frequently asked questions

Yes. The calculator implements the standard formula as documented and returns exact floating-point results. No approximations are used unless noted in the formula.
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