The International System of Units has declared the ampere, or amp, the unit of electrical current. The symbol for ampere is "A." Electric current is defined as any type of flow of electricity or electrons through a medium.

The flow of electrons through a medium, such as a wire, causes electricity to form. Electricity and electric current can be measured by Ohm's Law. This law exhibits the relationship between electric current, voltage and resistance. It states that electric current equals the amount of voltage multiplied by the total resistance of a medium. Current is measured in amps, voltage in volts and resistance in ohms. All three variables can be found by using Ohm's Law.