Electric current is the directed movement of charge carriers.

An electric current can occur when there are free charge carriers, electrons or ions, and when an electric force is applied to them. A current can operate continuously when a circuit is created.

A circuit is a necessary prerequisite for a steady electric current to occur. A circuit consists of a power source (battery, battery, generator), switch(es) (which can be used to turn the current on and off), consumer(s) of electricity, and wires.

In a series connection, electrical appliances are connected in series , or one after the other.

In a parallel connection, electrical appliances are connected in parallel .