A type of resistor that uses a thin layer of resistive material deposited on an insulating core. For low-power applications film resistors are more stable than composition resistors and except for very high precision requirements are smaller and less expensive than accurate wire-wound resistors.

Resistive materials used are crystalline carbon, boron-carbon, and various metallic oxides or precious metals. Film resistors usually have a continuous uniform film applied in a particular pattern to the core, the film thickness determining the resistance (see diagram). Higher resistances are obtained by using a spiral pattern of film on the core, the tighter the spiral the higher the resistance. High-power applications are limited by the film resistor's 200 ˚C maximum operating temperature but below this limit the resistance achieved for a given physical size is higher than that of the corresponding wire-wound resistor.

Flat thin- or thick-film resistors are also used in integrated circuits. These may be produced in a form suitable for hybrid integrated circuits or as an integral component in a fully integrated circuit.

Continuously adjustable film resistors are also produced; they may be either linear or circular and are actuated by a lead screw.

Types of film resistors