A coulomb is a measure of electric charge. It is defined as the quantity of electricity transported in one second by a current of one ampere. In other words, one coulomb is the amount of electric charge carried by a current of one ampere flowing for one second. It is approximately equal to the charge of 6.24 × 10^18 electrons or protons. This unit is named after the French physicist Charles-Augustin de Coulomb and is the standard unit of electric charge in the International System of Units (SI).