**Current** is the flow of electrons in an electric circuit. The symbol for current is an "I". Current is measured in amperes (often shortened to "amps"). The SI symbol for amps is an "A". Current which only flows in a single direction is known as *direct current* (DC) while current which alternates direction and flows back and forth is known as *alternating current* (AC).

## Technical things for those with an Extra license[]

In practical terms, the ampere is a measure of the amount of electric charge passing a point in an electric circuit per unit time with 6.241 × 1018 electrons, or one coulomb per second constituting one ampere.

The practical definition may lead to confusion with the definition of a coulomb (i.e., 1 ampere-second), but in practical terms this means that measures of a constant current (e.g., the nominal flow of charge per second through a simple circuit) will be defined in amperes (e.g., "a 20 mA circuit") and the flow of charge through a circuit over a period of time will be defined in coulombs (e.g., "a variable-current circuit that flows a total of 10 coulombs over 5 seconds"). In this way, amperes can be viewed as a flow rate, i.e. number of particles (charged) transiting per unit time, and coulombs simply as the number of particles.