|antique||[ e ] |
|modern||[ ɛ ] |
|From the ancient world||e|
|From the modern||e|
The character E originally comes from the Phoenician letter "he" and was used by the Greeks for the vowel "E". The name “ e psilón ” ( Gr. Ἔ ψιλόν ) means “simple” or “bare e” (compared to the letter combination “αι”, which has the same sound value as the ἔ ψιλόν since the Hellenistic period ).
- In phonetic transcription , epsilon stands for an unrounded, half-open front tongue vowel ( open e ).
- In mathematics , ε is used to denote an arbitrarily small number greater than zero. Such a number is needed in analysis when defining limit values such as supremum and infimum . This area is therefore also referred to as " epsilontics ".
- In some areas of mathematics, ε (x) describes a Heaviside function ,
- and in tensor calculus ε means the Levi-Civita symbol .
- Mathematicians and astronomers use ε (next to e ) for the numerical eccentricity of an ellipse or elliptical orbit .
- In astronomy , ε is
- In space travel, there is the epsilon (rocket) as part of the Japanese solid rocket series
- In geometry and geodesy , ε is often used for a small angle or a special angle difference , and
- in the compensation calculation for the error of a measured variable to be minimized .
- In computer science , the small epsilon (ε) stands for an empty word .
- In physics , ε denotes the permittivity , the coefficient of performance and the emissivity .
- In technical mechanics , it stands for the elongation ,
- and for internal combustion engines for the compression ratio .
- In chemistry , the small epsilon denotes the extinction coefficient .
- In economics , ε is often used for income elasticity (analogous to η for general elasticity) and for the real exchange rate , defined by: ε = nominal exchange rate * domestic price level / international price level.
- The symbol “3” (inverted epsilon) is the conformity symbol for compliance with the EC “Council Directive 75/324 / EEC” - approximation of the laws of the member states on aerosol dispensers from 1975, amended in 1980 and 1994. See also technical rule Pressurized gas TRG300 of the FRG on pressurized gas packs and declaration of conformity from the manufacturer of pressure equipment with more than low pressure hazard potential (CE mark).
- As a European conformity notice on high-pressure gas cylinders (stamped on the steel shoulder), it makes it easier for e.g. For example, compressed air or oxygen cylinders that have been tested in one EU country can also be filled in another EU country - in accordance with standards that became mandatory in 2006
- as “Ex” (E in the form of a large, small epsilon) in the circumscribed hexagon it stands for devices that are suitable for explosive environments.