Einheitsladungskontrolle
Einheitsladung, in physics often called the elementary charge and denoted e, is the fundamental unit of electric charge. It is the magnitude of the charge carried by a single proton, equal in absolute value to the charge of an electron, which is −e. In the International System of Units, e is defined exactly as 1.602176634×10−19 coulombs as part of the 2019 redefinition of the SI base units.
Charge in nature is observed to be quantized in units of e, so the total charge q
In everyday practice, charges are often expressed in units of the elementary charge, and e is used
History: The elementary charge was established experimentally in the early 20th century, notably by Millikan's oil-drop