Calcolatore Resistenza Filo
Calculate wire resistance from material and dimensions
Sommario
Come Usare
- Enter the wire length in meters
- Enter the wire diameter in millimeters
- Select the wire material (copper, aluminum, silver, or gold)
- Click calculate to see wire resistance
Wire Resistance Basics
Wire resistance depends on four factors: material resistivity, length, cross-sectional area, and temperature. Longer wires and smaller diameters increase resistance, while larger diameters decrease it.
Different materials have different resistivities. Silver has the lowest resistivity (best conductor), followed by copper, gold, and aluminum. Copper is most commonly used due to its good conductivity and lower cost than silver or gold.
Resistance Formula
- R = ρL/A
- Where R = resistance in ohms
- ρ (rho) = resistivity in ohm-meters
- L = length in meters
- A = cross-sectional area in square meters
- For circular wire: A = π(d/2)² = πr²
Applications
- Wire selection for circuits
- Heating element design
- Precision resistor manufacturing
- Cable sizing calculations
- Electromagnet design
- Current sensing applications
Domande frequenti
- Which material makes the best wire?
- Silver has the lowest resistivity and is the best conductor, but it's expensive. Copper is the most common choice, offering excellent conductivity at reasonable cost. Aluminum is lighter and cheaper but has higher resistance.
- How does temperature affect wire resistance?
- For most metals, resistance increases with temperature. This calculator uses standard room temperature (20°C) values. In practice, resistance can increase 30-40% at operating temperatures.
- Why does wire diameter matter more than length?
- Resistance is inversely proportional to the square of the radius (R ∝ 1/r²). Doubling the diameter reduces resistance by 4×, while doubling the length only doubles resistance. This is why thick wires are critical for high-current applications.
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