Definition
A fixed-value resistor made by depositing a thin film of metal alloy onto a ceramic core, then cutting a spiral groove through the film to set the resistance value. Metal-film resistors are valued for their close tolerance, low noise, and stable resistance across temperature changes.
Plain English
An electrical part that resists the flow of current by a known, precise amount. It is built by coating a small ceramic rod with a thin layer of metal and trimming that layer until the resistance is exactly right.
Context Anchor
Seen in aircraft electrical and avionics maintenance manuals, circuit diagrams, and component descriptions, more often by technicians than during normal cockpit operation.
Derivation
The name describes how it is built: a thin film of metal forms the resistive element, in contrast to older carbon-composition resistors that used a solid mix of carbon and binder.
Why Pilots Care
Pilots do not service these directly, but their accuracy is part of why modern avionics give consistent, reliable readings across wide temperature swings between the cockpit on the ramp and at altitude.
Grounding Statement
In a circuit that needs only a controlled amount of current, a metal-film resistor provides that control with a stable metal coating.
Intuition Check
“Film” here does not mean a movie or a loose sheet. It means a very thin coating of metal on an electrical part.
Example Sentence 1
The radio's circuit board uses metal-film resistors because they hold their value precisely as the avionics bay heats up in flight.
Example Sentence 2
Temperature changes in flight did not affect the metal-film resistor's value, keeping the instrument readings steady.