Resistors

A resistor is component of an electric circuit that resists the flow of direct or alternating electric current. Resistors can limit or divide the current, reduce the voltage, protect an electric circuit, or provide large amounts of heat or light.

An electric current is the movement of charged particles called electrons from one region to another. The amount of resistance to the flow of current that a resistor causes depends on the material it is made of as well as its size and shape. Resistors are usually placed in electric circuits, which are devices formed when current moves through an electrical conductor (a material that allows the current to flow without much resistance, such as copper wire) and when the conductor makes a complete loop.