Cable Impedance Calculator

Your details

Coaxial and twisted-pair modes calculate characteristic impedance from physical dimensions. AC mode calculates total impedance from resistance, inductance, and capacitance per unit length.
Outer diameter of the centre conductor.
mm
Inner diameter of the outer shielding conductor (i.e. the inner edge of the braid/foil).
mm
Dielectric constant of the insulating material between conductors. Solid PTFE: ~2.1, Solid polyethylene: ~2.3, Foamed PE: ~1.5, Air-spaced: ~1.0.
Characteristic impedance
67.84Ω

Characteristic impedance Z0 of the cable

Capacitance per metre74.618pF/m
Inductance per metre342.96nH/m
Propagation delay5.059ns/m
Cutoff frequency21.33GHz
67.84 Ohm
< 50 Ohm<5050-75 Ohm (standard)50-7575-150 Ohm (video/RF)75-150> 150 Ohm150+

Characteristic impedance: 67.8 Ohm

  • Signal propagation delay: 5.06 ns per metre.
  • Distributed capacitance: 74.6 pF/m.
  • The TE11 cutoff frequency is 21.33 GHz; above this frequency higher-order modes can propagate and degrade signal integrity.

Next stepVerify that your termination impedance matches the cable characteristic impedance to avoid signal reflections and standing waves.

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