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DC Resistance Formula:
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DC resistance refers to the opposition that a conductor presents to the flow of direct current. It depends on the material's resistivity, the length of the conductor, and its cross-sectional area according to the fundamental formula: R = ρL/A.
The calculator uses the DC resistance formula:
Where:
Explanation: The resistance increases with length and resistivity, but decreases with larger cross-sectional area. This relationship forms the basis for designing electrical conductors and calculating power losses.
Details: Accurate DC resistance calculation is crucial for electrical system design, power transmission efficiency, voltage drop calculations, and selecting appropriate conductor sizes for various applications.
Tips: Enter resistivity in Ω·m, length in meters, and cross-sectional area in square meters. All values must be positive numbers. Common resistivity values: Copper = 1.68×10⁻⁸ Ω·m, Aluminum = 2.82×10⁻⁸ Ω·m.
Q1: What is the difference between DC and AC resistance?
A: DC resistance considers only the material's inherent opposition to current flow, while AC resistance includes additional effects like skin effect and proximity effect that increase resistance at higher frequencies.
Q2: How does temperature affect DC resistance?
A: Resistance increases with temperature for most conductors. The relationship is approximately linear: R₂ = R₁[1 + α(T₂ - T₁)], where α is the temperature coefficient.
Q3: What are typical resistivity values for common conductors?
A: Copper: 1.68×10⁻⁸ Ω·m, Aluminum: 2.82×10⁻⁸ Ω·m, Silver: 1.59×10⁻⁸ Ω·m, Gold: 2.44×10⁻⁸ Ω·m.
Q4: Why does resistance decrease with larger cross-sectional area?
A: Larger cross-sectional area provides more pathways for electrons to flow, reducing the overall opposition to current flow, similar to how wider pipes allow more water to flow with less resistance.
Q5: How is this formula used in practical applications?
A: Used in electrical wiring design, power transmission systems, electronic circuit design, and determining voltage drops in electrical installations to ensure proper equipment operation.