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For gases (e.g. nitrogen, sulfur hexafluoride) it normally decreases with increased humidity as ions in water can provide conductive channels. For gases it increases with pressure according to Paschen's law; For air, dielectric strength increases slightly as the absolute humidity increases but decreases with an increase in relative humidity [2]
The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insulator measures the ability of the insulator to store electric energy in an electrical field.
This is about 14 times greater than the field strength for the 1.5-metre gap. The phenomenon is well verified experimentally and is referred to as the Paschen minimum. The equation loses accuracy for gaps under about 10 μm in air at one atmosphere [ 9 ] and incorrectly predicts an infinite arc voltage at a gap of about 2.7 μm.
In general, permittivity is not a constant, as it can vary with the position in the medium, the frequency of the field applied, humidity, temperature, and other parameters. In a nonlinear medium, the permittivity can depend on the strength of the electric field. Permittivity as a function of frequency can take on real or complex values.
In electricity (electromagnetism), the electric susceptibility (; Latin: susceptibilis "receptive") is a dimensionless proportionality constant that indicates the degree of polarization of a dielectric material in response to an applied electric field. The greater the electric susceptibility, the greater the ability of a material to polarize in ...
For high voltage applications, a good dielectric gas should have high dielectric strength, high thermal stability and chemical inertness against the construction materials used, non-flammability and low toxicity, low boiling point, good heat transfer properties, and low cost. [1] The most common dielectric gas is air, due to its ubiquity and ...
When the electric field strength between the two exceeds the dielectric strength of the air, discharge will occur and break through the air. [15] During the lightning discharge process, charged particles bombard the surrounding air molecules, ionizing the molecules to generate negative air ions. At the moment of the lightning strike, hundreds ...
A corona discharge occurs at locations where the strength of the electric field (potential gradient) around a conductor exceeds the dielectric strength of the air. It is often seen as a bluish glow in the air adjacent to pointed metal conductors carrying high voltages, and emits light by the same mechanism as a gas discharge lamp ...