Permittivity

Permittivity, also known as the dielectric constant, is a fundamental concept in electrodynamics. It describes how strongly a material influences electric fields. More precisely, permittivity indicates how much electric charge is necessary to generate a specific electric field in a material. It is a measure of how well a material can conduct or "permit" electric field lines.

Expressed in mathematical form, the permittivity of a material is the ratio of the electric flux density (D) to the electric field strength (E). Absolute permittivity is measured in farads per metre (F/m) and is composed of the permittivity of a vacuum (ε₀) and the relative permittivity (εr) of the material: ε = ε₀ * εr. The permittivity of a vacuum, also known as the electric constant, is a fixed value, while the relative permittivity varies depending on the material.

A higher value of relative permittivity means that the material has the ability to attenuate electric field lines more strongly and thus to insulate electric fields better. This property is particularly important in the manufacture of capacitors and other electronic components, where control over electric fields is of decisive importance.