Below depicts a 100m 3-pair STP cable, where my focus is the pair 1 on the top:


simulate this circuit – Schematic created using CircuitLab

If I know the output impedance of the source Rs, and if I want to calculate the LP filter effect of the cable on the V1 signal; how can I calculate the total capacitance C1 for the Pair 1.

How can I calculate the total capacitance of the pair from the data-sheet like this one? Which parameters should be taken into account?

(Consider the signal frequency V1 is low like 100Hz(sinusoidal), I guess we can neglect the transmission line effects)


1 Answer 1


The capacitance is right in the datasheet:

enter image description here

  • \$\begingroup\$ We dont use capacitance unbalance? What is that one? Thanks \$\endgroup\$
    – user1999
    May 28, 2018 at 6:46
  • \$\begingroup\$ Secondly which parameter shows me to calculate total Rcable in my figure? I mean DC resistance per meter \$\endgroup\$
    – user1999
    May 28, 2018 at 6:47
  • \$\begingroup\$ @newage2000 look at the table and read it. \$\endgroup\$
    – Andy aka
    May 28, 2018 at 8:47

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