Planck impedance

The Planck impedance is the unit of electrical resistance, denoted by Z_P, in the system of natural units known as Planck units.

$Z\_P\; =\; frac\{V\_P\}\{I\_P\}\; =\; frac\{1\}\{4\; pi\; epsilon\_0\; c\}\; =\; frac\{Z\_0\}\{4\; pi\}\; approx$ 29.9792458 Ω

where

$V\_P$ is the Planck voltage

$I\_P$ is the Planck current

$c$ is the speed of light in a vacuum

$epsilon\_0$ is the permittivity of free space

$Z\_0$ is the impedance of free space

See also

*Planck's constant
*Natural units