What is current measured in?

Electrical current is measured in amperes. The unit symbol for ampere is "A," without the quotes. The dimension symbol for electrical current is "I," also without the quotes. Therefore, "I = 3 A" means the electrical current is 3 amperes.

A current of 1 ampere means that there is one coulomb of charge passing through a wire every second. Ampere is one of the International System of Units base units, meaning other SI units of measurement are derived from it. For example, the coulomb, with a unit symbol of "C," is a unit of electrical charge and can be mathematically expressed as "1 C = 1 A * 1 s."