Skin Depth Calculator
Calculate electromagnetic skin depth from frequency, conductivity, and permeability for AC current penetration depth.
What Is Skin Depth?
Skin depth (δ) is the distance below the surface of a conductor where alternating current density falls to about 37% of its surface value. At higher frequencies, current crowds near the surface and the effective cross-section shrinks, increasing AC resistance.
Skin Depth Formula
$$\delta = \sqrt{\frac{2}{\omega \mu \sigma}} = \sqrt{\frac{1}{\pi f \mu \sigma}}$$Here \(f\) is frequency in hertz, \(\mu = \mu_0 \mu_r\) is absolute permeability, and \(\sigma\) is electrical conductivity in siemens per meter. For copper at 1 MHz, skin depth is on the order of tens of micrometers.
Practical Applications
Skin effect matters in RF cables, transformer windings, induction heating, and nondestructive testing. Engineers use skin depth to estimate how deeply eddy currents penetrate and to size conductors for high-frequency circuits.
Related tools: Impedance Matching Calculator and Cable Impedance Calculator.
Frequently Asked Questions
Why does skin depth decrease with frequency?
Higher frequency means faster field changes, so induced eddy currents oppose penetration deeper into the conductor. Current stays closer to the surface and skin depth shrinks.
Does skin depth apply to DC current?
No. Skin effect is an AC phenomenon. Direct current uses the full conductor cross-section uniformly.
How does conductivity affect skin depth?
More conductive materials have smaller skin depth at the same frequency because opposing currents build up faster near the surface.
What is the relationship between skin depth and AC resistance?
When skin depth is much smaller than the conductor radius, effective area drops and AC resistance rises above the DC value.
Do magnetic materials behave differently?
Yes. Higher relative permeability reduces skin depth because magnetic fields interact more strongly with the material.
Related Tools
Meta Tag Generator
JSON To MobX State Tree
End Portal Finder
Remove Comments
Kepler's Third Law Calculator
Pick a Number
Fixed Asset Turnover Calculator
Tenure
Fake Tweet Generator
Mileage Reimbursement Calculator
Mean Free Path Calculator
Add List Item Counter
Cholesky Decomposition Calculator
Similar Triangles Calculator
Electrical Power Calculator
Division Word Problems
Write Integers in Fancy Font
Linear Regression Calculator
Random Object Generator
Maze Generator