Editing Skin effect (section)

===== Telephone cable =====

Representative parameter data for 24 gauge PIC telephone cable at {{convert|21|C|F}}.
:{| class="wikitable" style="text-align:right;"
|-
! Frequency<br/>(Hz) !! R<br/>(Ω/km) !! L<br/>(mH/km) !! G<br/>(μS/km) !! C<br/>(nF/km)
|-
| 1&nbsp;&nbsp;Hz   || 172.24 || 0.6129 || 0.000 || 51.57
|-
|   1&nbsp;kHz   || 172.28 || 0.6125 || 0.072 || 51.57
|-
|  10&nbsp;kHz   || 172.70 || 0.6099 || 0.531 || 51.57
|-
| 100&nbsp;kHz   || 191.63 || 0.5807 || 3.327 || 51.57
|-
|   1&nbsp;MHz   || 463.59 || 0.5062 || 29.111 || 51.57
|-
|   2&nbsp;MHz   || 643.14 || 0.4862 || 53.205 || 51.57
|-
|   5&nbsp;MHz   || 999.41 || 0.4675  || 118.074 || 51.57
|}
More extensive tables and tables for other gauges, temperatures and types are available in Reeve.<ref name="Reeve558">{{Harvtxt|Reeve|1995|p=558}}</ref>
Chen<ref name="Chen26">{{Harvtxt|Chen|2004|p=26}}</ref> gives the same data in a parameterized form that he states is usable up to 50&nbsp;MHz.

Chen<ref name="Chen26" /> gives an equation of this form for telephone twisted pair:
<math display="block"> L(f) = \frac {\ell_0 + \ell_\infty \left(\frac{f}{f_m}\right)^b }{1 + \left(\frac{f}{f_m}\right)^b} \, </math>