A measure of electrical current flow, also called amps for short. It literally equates to the number of electrons in a conductor flowing past a certain point in a given amount of time. Without going into an electronics course here, current is “drawn” from a supply of power due to the presence of a voltage being placed across a load. Uh, in English please? A typical electrical outlet is a good example. There is a 120 volt potential there (think of the voltage as “pressure”), but no current flow. Put some type of load across the outlet (like a light bulb) and you now have a complete circuit in which electrical current can flow. Current will flow according to how much resistance there is to the flow. High resistance (impedance) will yield less current flow than low resistance. Amps are a measure of this current flow. A direct short (no resistance) will cause a very large amount of current to flow and, if the supply is capable of delivering enough amperage, the wire will eventually heat up and melt (possibly causing a fire in the process). That’s why we have fuses and circuit breakers. They limit current flow by opening (the opposite of shorting) a circuit before this happens. A 15 amp breaker will trip when the load(s) in that circuit try to pull in excess of 15 amps of current.