Wire Pair Resistance
Wire pair Resistance Model
DC resistance of a wire pair is:
Units: Ohms
AC resistance of a wire pair is:
Units: Ohms
Skin Depth is:
Units: meters
Description
Resistance calculated using this tool includes both dc and ac resistance of the wire pair. At low frequencies, where skin depth is greater than wire radius, ac resistance is approximately the same as the dc resistance. As frequency increases, ac resistance increases.
Assumptions and Limitations
Dimensions are in meters.
Wires are assumed to have uniform circular cross section and to be uniformly spaced over their length. Separation between the wires is assumed to be large enough that proximity effect may be ignored.
Wire relative permeability: 
Wire relative conductivity: 
Constants
Permeability of free space: 
H/m
Conductivity of copper: 
= 5.98 x 10 7 S/m (Siemens per meter) at 20-degrees C
Reference: “Analysis of Multiconductor Transmission Lines,” 2nd Ed., Clayton R. Paul, 2008.
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