Skin Effect Calculator Formula
Understand the math behind the skin effect calculator. Each variable explained with a worked example.
Formulas Used
Skin Depth
skin_depth_mm = sqrt(rho_ohm_m / (pi * freq_hz * rel_permeability * 4 * pi * 1e-7)) * 1000Variables
| Variable | Description | Default |
|---|---|---|
frequency_mhz | Frequency(MHz) | 1 |
resistivity_uohm_cm | Resistivity(uΩ-cm) | 1.72 |
rel_permeability | Relative Permeability | 1 |
freq_hz | Derived value= frequency_mhz * 1000000 | calculated |
rho_ohm_m | Derived value= resistivity_uohm_cm * 1e-8 | calculated |
How It Works
Skin Effect
delta = sqrt(rho / (pi x f x mu))
At high frequencies, current concentrates near the conductor surface. The skin depth is the depth at which current density falls to 1/e (37%) of the surface value.
Copper at 1 MHz: skin depth is about 0.066 mm.
Worked Example
Copper at 1 MHz.
frequency_mhz = 1resistivity_uohm_cm = 1.72rel_permeability = 1
- 01rho = 1.72e-8 ohm-m
- 02mu = 4pi x 1e-7 H/m
- 03delta = sqrt(1.72e-8 / (pi x 1e6 x 4pi x 1e-7))
- 04delta = 0.066 mm
Frequently Asked Questions
Why does skin effect matter?
At high frequencies, effective wire area decreases, increasing AC resistance. RF designers must account for this.
How to mitigate skin effect?
Use Litz wire (many thin insulated strands) or hollow conductors for RF applications.
Does skin effect occur at 60 Hz?
Yes, but skin depth in copper at 60 Hz is about 8.5 mm, only affecting very large conductors.
Ready to run the numbers?
Open Skin Effect Calculator