Material

Temp

perm.

resis.

depth (mm) at frequency (Hz)

K

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

\delta = \sqrt{ 2 \rho / \omega \mu_r \mu_0 } in meters
~=~ \sqrt{ 2.533e11 \rho / f \mu_r } ~~ in mm

2 / 2 \pi \mu_0 = 253303 m/H

Resistivity

for copper see
Matula 1979 page 1161

for aluminum see Simmons 1960

Graph by Zureks
from Wikipedia
article skin effect

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