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Skin Effect Depth Calculator
This calculator determines the skin depth of a conductor at a selected frequency. Skin depth is the distance below the conductor surface where current density falls to about 37% of its surface value. It is useful for RF design, PCB copper analysis, high-frequency conductors, transformers, and EMI-related calculations.
Input Parameters
Result
Lower skin depth means the current is concentrated closer to the conductor surface, which increases effective AC resistance at high frequency.
Equations Used
Skin Depth Formula:
δ = √(ρ / (π × f × μ))
Where:
δ = skin depth in meters
ρ = resistivity in ohm-meter
f = frequency in Hz
μ = μ0 × μr
μ0 = 4π × 10-7 H/m
μr = relative permeability of the conductor material
Frequently Asked Questions (FAQ)
Q1: What is skin depth?
Skin depth is the depth below a conductor surface where current density drops to approximately
37% of the current density at the surface.
Q2: Why does skin depth matter?
At high frequencies, current flows mainly near the conductor surface. This reduces effective
conducting area and increases AC resistance.
Q3: How does frequency affect skin depth?
Higher frequency produces smaller skin depth. This is why RF conductors, PCB traces,
and high-frequency windings require careful conductor design.
Q4: Why do different materials have different skin depth?
Skin depth depends on resistivity and magnetic permeability. Materials such as copper and silver
have lower resistivity, while magnetic materials can have much higher relative permeability.
Q5: Is this useful for PCB design?
Yes. It helps estimate whether high-frequency current is using the full copper thickness or only
a thin surface layer of the PCB trace.
Q6: Why are nickel and iron values approximate?
Magnetic materials can have permeability that changes with alloy, heat treatment, magnetic field,
and frequency. Use manufacturer data for precision design.
