Definition
A three-terminal variable resistor used to provide an adjustable voltage output. Voltage is applied across the two outer terminals, and a movable wiper contact taps off a portion of that voltage at the third terminal, producing an output that varies with the wiper's position.
Plain English
An adjustable resistor with a sliding or rotating contact that lets you pick off any voltage between zero and the full supply voltage. Turn the knob one way and the output voltage goes up; turn it the other way and it goes down.
Context Anchor
Seen in aircraft electrical systems, cockpit light dimmers, control-position sensors, and maintenance troubleshooting of instruments or indicators.
Derivation
From 'potential' (meaning electrical voltage) plus the Greek 'metron' (measure). It was originally an instrument used to measure unknown voltages by comparing them against a known adjustable voltage. The modern component keeps the same idea: it lets you set a chosen voltage by position.
Why Pilots Care
Potentiometers supply continuous position feedback to autopilots, engine controls, and flight instruments; a failing unit produces erratic readings that affect handling and system accuracy.
Analogy
Think of a dimmer switch on a household light. The wall supplies a fixed voltage, but the dimmer lets you choose how much of it actually reaches the bulb. A potentiometer does the same job for an electrical signal.
Intuition Check
Do not assume a potentiometer is only a meter that displays a reading. In aircraft use, it is often an adjustable part inside a control or sensor that changes an electrical signal.
Example Sentence 1
The technician traced the dim panel lighting to a worn potentiometer in the dimmer control.
Example Sentence 2
A worn potentiometer in the flap system caused the position indicator to jump between two readings during approach.