Physics
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Conductor Resistance vs Temperature.
Calculates the resistance of a conductor at a target temperature given its resistance at a reference temperature and the temperature coefficient of resistance.
Your inputs
How it works
- 1
Enter the resistance at the reference temperature.
- 2
Enter the reference temperature and the target temperature.
- 3
Enter the temperature coefficient of resistance for the material.
- 4
The calculator applies the linear formula to find the resistance at the target temperature.
r_ref * (1 + alpha * (t_target - t_ref))Frequently asked questions
What is the temperature coefficient of resistance?
It is a material property that indicates how much the resistance changes per degree Celsius change in temperature. For metals like copper, it is positive, meaning resistance increases with temperature.
Is this formula accurate for all temperature ranges?
The linear approximation works well for moderate temperature changes. For very large temperature swings, the relationship becomes nonlinear, and more complex models may be needed.
What if the target temperature is lower than the reference?
The formula still works; the resistance will decrease if the temperature coefficient is positive. For example, cooling a copper conductor reduces its resistance.
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Results
Formula checkedEstimate for general guidance only — verify important decisions with an appropriate professional.
How it works
Calculates the resistance of a conductor at a target temperature given its resistance at a reference temperature and the temperature coefficient of resistance.
- Enter the resistance at the reference temperature.
- Enter the reference temperature and the target temperature.
- Enter the temperature coefficient of resistance for the material.
- The calculator applies the linear formula to find the resistance at the target temperature.
Formulas
The math behind this calculator, written out so you can verify the result.
Linear resistance-temperature relation
R(T) is the resistance at temperature T, R₀ is the resistance at reference temperature T₀, and α is the temperature coefficient of resistance.
Example:
Input: R₀ = 10 Ω, T₀ = 20°C, T = 75°C, α = 0.00393 /°C
Calculation: 10 × (1 + 0.00393 × (75 - 20))
Result: ≈ 12.16 Ω
Real-world use cases
Where this calculation shows up in everyday life.
Electrical engineering design
Predict how wire resistance changes with operating temperature to ensure circuits function correctly.
Example: Designing a power cable that will operate at 75°C.
Temperature sensing
Resistance temperature detectors (RTDs) use this principle to measure temperature.
Example: A platinum RTD with known α.
Safety analysis
Estimate resistance increase in conductors under load to assess overheating risks.
Example: Checking if a wire's resistance at high current could cause excessive voltage drop.
Tips and common mistakes
Tips
- Use the material's specific α value; common values: copper 0.00393, aluminum 0.00403, iron 0.005.
- Ensure the reference temperature matches the conditions under which R₀ was measured.
- For precision, consider that α itself can vary slightly with temperature.
- This linear model is valid for a limited range; for extreme temperatures, use more advanced models.
Common Mistakes to Avoid
- Using α as a percentage instead of a decimal (e.g., 0.5 instead of 0.005).
- Forgetting to convert temperature differences to the same unit (always use °C or K consistently).
- Assuming the formula works for superconductors or materials with negative α without checking.
Assumptions and limitations
- Use the stated inputs and units.
- Results are estimates for planning and education.
- Check measurements and source data before making an important decision.