1. What is Skin Depth?

Skin depth (δ) is the distance from the surface of a conductor where the current density has fallen to 1/e (about 37%) of its value at the surface. It's a critical parameter in high-frequency electronics and electromagnetic applications.

2. How Does the Calculator Work?

The calculator uses the skin depth equation:

Where:

• \( \delta \) — Skin depth (m)
• \( \rho \) — Resistivity of the conductor (Ω·m)
• \( f \) — Frequency of the AC current (Hz)
• \( \mu \) — Permeability of the conductor (H/m)

Explanation: The equation shows that skin depth decreases with increasing frequency, permeability, and conductivity of the material.

3. Importance of Skin Depth Calculation

Details: Skin depth is crucial for designing high-frequency circuits, transmission lines, and electromagnetic shielding. It helps determine conductor sizing and predict power losses in AC systems.

4. Using the Calculator

Tips: Enter resistivity in Ω·m, frequency in Hz, and permeability in H/m. The default permeability value is for free space (μ₀ = 4π×10⁻⁷ H/m). All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical skin depth for copper at 1 MHz?
A: About 0.066 mm (66 μm), as copper has ρ ≈ 1.68×10⁻⁸ Ω·m and μ ≈ μ₀.

Q2: Why does skin depth matter in cable design?
A: At high frequencies, current flows mostly near the surface, so the center of thick conductors is unused. This affects cable sizing and power handling.

Q3: How does temperature affect skin depth?
A: Higher temperatures increase resistivity (ρ), which increases skin depth. This is important in high-current applications.

Q4: What's the relationship between skin depth and frequency?
A: Skin depth is inversely proportional to the square root of frequency (δ ∝ 1/√f). Higher frequencies have shallower skin depths.

Q5: When is skin effect negligible?
A: At low frequencies or with small conductors where the skin depth is larger than the conductor's radius.