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| || Material                 || Temp || perm.  ||   res. ||<-6> depth (m) at frequency                                || || || K || μ,,r,, || Ω-m || 60 Hz || 400 Hz || 1 KHz || 5 KHz || 20 KHz || 200 KHz || || 3% Si Transformer Steel || 300 || 700 || || || || || || || || || 3% Si Transformer Steel || 700 || 700? || || || || || || || || || Aluminum || 300 || 1 || || || || || || || || || Aluminum || 700 || 1 || || || || || || || || || Copper || 300 || 1 || || || || || || || || || Copper || 700 || 1 || || || || || || || || | $ \delta = \sqrt{ 2 \rho / \omega \mu_r \mu_0 } $ in m $ ~=~ \sqrt{ 2.533e11 \rho / f \mu_r } ~~$ in mm $ ~~~~~~ 2 / 2 \pi \mu_0 $ = 253303 m/H || Material || Temp || perm. || resis. ||<-7> depth (mm) at frequency (Hz) || || || K || $\mu_r$||$\rho~~\Omega$-m || 1 Hz || 60 Hz || 400 Hz || 1 KHz || 5 KHz || 20 KHz || 200 KHz || || 3% Si Transformer Steel || 300 || 700 || 5e-7 || 13 || 1.7 || 0.67 || 0.43 || 0.19 || 0.95 || 0.030 || || 3% Si Transformer Steel || 600 || 300? || 7e-7? || 24 || 3.1 || 1.2 || 0.77 || 0.34 || 0.17 || 0.054 || || Copper || 300 || 1 || 1.7e-8 || 66 || 8.5 || 3.3 || 2.1 || 0.93 || 0.46 || 0.15 || || Copper || 600 || 1 || 3.8e-8 || 98 || 13 || 4.9 || 3.1 || 1.4 || 0.69 || 0.22 || || Aluminum || 300 || 1 || 2.8e-8 || 84 || 11 || 4.2 || 2.7 || 1.2 || 0.60 || 0.19 || || Aluminum || 600 || 1 || 5.9e-8 || 122 || 16 || 6.1 || 3.9 || 1.7 || 0.86 || 0.27 || || '''Resistivity'''<<BR>><<BR>> for copper see <<BR>> Matula 1979 page 1161<<BR>>for aluminum see Simmons 1960 ||<-10> {{ https://upload.wikimedia.org/wikipedia/commons/f/f3/Skin_depth_by_Zureks.png }} || || Graph by [[https://commons.wikimedia.org/wiki/User:Zureks | Zureks]]<<BR>>from Wikipedia<<BR>>article [[ https://en.wikipedia.org/wiki/Skin_effect | skin effect ]] || || [[ attachment:skindepth.ods | LibreOffice Spreadsheet]] || | 
Skin Depth
\delta = \sqrt{ 2 \rho / \omega \mu_r \mu_0 } in m ~=~ \sqrt{ 2.533e11 \rho / f \mu_r } ~~ in mm ~~~~~~ 2 / 2 \pi \mu_0 = 253303 m/H
| Material | Temp | perm. | resis. | depth (mm) at frequency (Hz) | ||||||
| 
 | K | \mu_r | \rho~~\Omega-m | 1 Hz | 60 Hz | 400 Hz | 1 KHz | 5 KHz | 20 KHz | 200 KHz | 
| 3% Si Transformer Steel | 300 | 700 | 5e-7 | 13 | 1.7 | 0.67 | 0.43 | 0.19 | 0.95 | 0.030 | 
| 3% Si Transformer Steel | 600 | 300? | 7e-7? | 24 | 3.1 | 1.2 | 0.77 | 0.34 | 0.17 | 0.054 | 
| Copper | 300 | 1 | 1.7e-8 | 66 | 8.5 | 3.3 | 2.1 | 0.93 | 0.46 | 0.15 | 
| Copper | 600 | 1 | 3.8e-8 | 98 | 13 | 4.9 | 3.1 | 1.4 | 0.69 | 0.22 | 
| Aluminum | 300 | 1 | 2.8e-8 | 84 | 11 | 4.2 | 2.7 | 1.2 | 0.60 | 0.19 | 
| Aluminum | 600 | 1 | 5.9e-8 | 122 | 16 | 6.1 | 3.9 | 1.7 | 0.86 | 0.27 | 
|  Resistivity |   | |||||||||
|  Graph by Zureks | ||||||||||

