Coulomb
Physical unit | |
---|---|
Unit name | Coulomb |
Unit symbol | |
Physical quantity (s) | Electric charge |
Formula symbol | , |
dimension | |
system | International system of units |
In SI units | |
Named after | Charles Augustin de Coulomb |
Derived from | Amps , second |
See also: ampere hour |
The coulomb [ kuˈlõː ] ( unit symbol : C, formerly Cb) is the derived SI unit of the electrical charge ( symbol Q or q ). It is named after the French physicist Charles Augustin de Coulomb .
1 Coulomb is the electric charge is transported within one second by the cross-section of a conductor in which an electric current of the strength of an ampere flows:
The coulomb is therefore also referred to as the ampere second (As). The ampere hour (Ah) that is customary to indicate the battery capacity is 3600 As = 3600 C.
definition
The definition of the units coulomb and ampere is based on the elementary charge , which has been determined to be exact , see International System of Units .
Historical
The Coulomb has replaced the electrostatic CGS unit ESU or Franklin (Fr):
at the speed of light
The two English electrical engineers Josiah Latimer Clark and Charles Tilston Bright proposed the farad as a unit for the electrical charge in 1861 in honor of the English physicist Michael Faraday . In 1881, however , the International Electricity Congress established the coulomb as the unit for electrical charge and the farad as the unit for electrical capacity .
The current definition of the coulomb by determining the elementary charge was adopted on November 16, 2018 at the 26th General Conference on Weights and Measures and came into force on May 20, 2019. Previously, the ampere was defined as the Lorentz force of an electric current, and the coulomb as one ampere second.
Web links
swell
- Le Système international d'unités, 9e édition, 2019 , the so-called "SI brochure", BIPM (English, French)