免费电流密度计算器
计算导体中的电流密度J=I/A。
A
mm²
Current Density
4,000,000 A/m²
Current Density4.00 A/mm²
Current Density vs Current
公式
Current Density
Current density describes how much current flows through a unit area of a conductor.
Formula
J = I / A
where I is the current and A is the cross-sectional area of the conductor. High current density causes excessive heating.
计算示例
10 A through a wire with 2.5 mm² cross-section.
- 01J = I / A
- 02J = 10 / 2.5 mm²
- 03J = 4 A/mm²
- 04J = 4,000,000 A/m²
常见问题
What is a safe current density for copper wire?
For continuous operation, copper wire should typically not exceed about 4 to 6 A/mm². Higher densities cause excessive heating.
Why does current density matter?
Current density determines resistive heating in the conductor. Exceeding safe limits can melt insulation or cause fires.
Is current density uniform across a wire?
At DC, yes. At high AC frequencies, the skin effect causes current to concentrate near the wire surface, increasing effective current density.
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