Calculate characteristic impedance of transmission lines and cables.
Cable Geometry
Outer diameter of the center wire (mm)
Inner diameter of the outer braid (mm)
Relative permittivity of insulation
D (Shield)
d (Core)
Characteristics
Impedance (Z₀)60.3 Ω
Velocity Factor65.9%Speed of signal vs Light speed
Capacitance83.7pF/m
Inductance304.9nH/m
Overview
Cable impedance is the opposition to AC current flow in transmission lines. Common values are 50Ω (RF), 75Ω (video), and 600Ω (audio). Matching impedance prevents signal reflection and loss.
💡
Pro Tips
50Ω is standard for RF and ham radio applications.
75Ω is used for video, cable TV, and satellite.
Impedance mismatches cause signal reflection and standing waves.
Cable length matters when it approaches wavelength of signal.
!
Fun Facts
"Coaxial cable impedance depends on conductor spacing and dielectric."
"Twisted pair Ethernet cables are 100Ω differential impedance."
"Speaker wire impedance is typically negligible for short runs."
"VSWR measures impedance matching quality (1:1 is perfect)."
Formula: Z₀ = √(L/C) where L = inductance, C = capacitance per unit length
