A fixed resistor is an electrical component with a fixed resistance that can not be changed. Resistors are used to reduce current and voltage in an electrical circuit. Common resistors feature a series of color-coded stripes to indicate resistance and tolerance.
There are four types of fixed resistors. The first type is carbon film, which uses a helical path of amorphous carbon to reduce voltage and current. The second type is metal film, which uses a helical path of nickel chromium to reduce voltage and current. These resistors have tighter tolerances than carbon film resistors. The third type of fixed resistor is wire wound, which are made of wire wound around a plastic or ceramic core. These resistors are used for their high voltage tolerance. The fourth type is surface mount, which is a more compact version of the metal film resistor.