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A uniform line terminated in its characteristic impedance will have no standing waves, no reflections from the end, and a constant ratio of voltage to current at a given frequency at every point on the line.

If the line is not uniform, the iterative impedance must be used.

The characteristic impedance of a linear, homogeneous, isotropic, dielectric propagation medium free of electric charge is given by the relation

where

is the characteristic impedance

is the magnetic permeabilityPermeability has several meanings: # In electromagnetism, permeability is the degree of magnetisation of a material in response to a magnetic field. In geology, permeability is a measure of the ability of a material to transmit fluids through it. of the medium

is the electric permittivityIn electromagnetism, permittivity ε is a measure of how much a medium changes to absorb energy when subject to an electric field. It is defined as the ratio D / E where D is the electric displacement by the medium and E is the electric field stren of the medium

is the speed of propagation in the medium

When the medium is free spaceIn physics, free space is a concept of electromagnetic theory, corresponding roughly to the vacuum, the baseline state of the electromagnetic field, or the replacement for the electromagnetic aether. It occurs in the expressions permittivity of free space, the magnetic permeability and electric permittivity of free space are used and this defines the universal physical constantIn science, a physical constant is a physical quantity whose numerical value does not change. It can be contrasted with a mathematical constant, which is a fixed value that does not directly involve a physical measurement. There are many physical constant, the characteristic impedance of free space :

here is the speed of propagationCherenkov effect in a "swimming pool" nuclear reactor. The effect is due to electrons moving faster than the speed at which light moves in water. The speed of light (denoted as c reputedly from the Latin celeritas "speed", and also known as Einstein's con in vacuum.

1 See also

• Maxwell's equationsMaxwell's equations are the set of four equations, attributed to James Clerk Maxwell, that describe the behavior of both the electric and magnetic fields, as well as their interactions with matter. Introduction Maxwell's four equations express, respective.

2 Source

Adapted from

• Federal Standard 1037CFederal Standard 1037C entitled Telecommunications: Glossary of Telecommunication Terms is a U. Federal Standard, issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, as amended. This docu.