Definition
A variable resistor in which a sliding contact moves along a length of resistance wire, tapping off a voltage that varies with the contact's position. It is used in aircraft instruments and control systems to convert mechanical position into a proportional electrical signal.
Plain English
A device with a wire and a sliding pointer. As the pointer moves along the wire, the electrical signal it sends out changes. This lets the system measure where something is by reading the voltage.
Context Anchor
Seen in aircraft electrical, instrument, and maintenance discussions where a system needs to sense or send position information.
Derivation
Potentiometer comes from 'potential' (voltage) and '-meter' (to measure) -- a device that measures or divides voltage. 'Slide-wire' describes how it does it: a contact slides along a length of wire rather than rotating like a knob-style potentiometer.
Why Pilots Care
Many cockpit indications -- fuel level, flap position, trim position -- rely on slide-wire potentiometers to send accurate position data to the gauge. When a reading drifts, sticks, or jumps, a worn or dirty slide-wire is often the cause.
Analogy
It works much like an old-style volume slider on a radio: as the slider moves, the electrical output changes smoothly from low to high.
Intuition Check
A slide-wire potentiometer does not make electrical power. It changes or measures an existing electrical signal based on where the sliding contact is.
Example Sentence 1
The flap position indicator gets its signal from a slide-wire potentiometer mounted on the flap actuator.
Example Sentence 2
During instrument overhaul the technician checked the resistance range of the slide-wire potentiometer to confirm smooth operation across the full travel.