|Name||Symbol||Derived quantity||Expressed in terms of SI base units|
|coulomb||C||electric charge||s A|
The coulomb, symbol C, is the SI coherent derived unit of electric charge.
One coulomb is the charge transported by a constant current of one ampere in one second.
The coulomb is named after the French physicist, Charles-Augustin de Coulomb (1736 – 1806).
The fixed numerical value of the elementary charge, e, is defined as 1.602 176 634 × 10−19 C. This definition implies the exact relation e = 1.602 176 634 × 10−19 C. Inverting this relation gives an exact expression for the coulomb in terms of the defining constant e:
The effect of this definition is that one coulomb is exactly 1/(1.602 176 634 × 10−19) of the value of the elementary charge, e.