Definition
A small temperature-sensing component shaped as a tiny bead of semiconductor material whose electrical resistance changes sharply with temperature. The bead is typically encased in glass with two fine wire leads, allowing it to respond quickly to temperature changes in the air or surface it contacts.
Plain English
A very small bead-shaped sensor that changes its electrical resistance as it gets hotter or colder, used to measure temperature.
Context Anchor
Seen in aircraft electrical-system, engine-instrument, and temperature-control system descriptions.
Derivation
Thermistor is a blend of 'thermal' (heat) and 'resistor' (a component that resists electrical current). 'Bead' describes the physical shape. The name tells you exactly what it is: a small bead-shaped resistor whose resistance depends on heat.
Why Pilots Care
Provides accurate temperature data for engine monitoring and outside air temperature systems.
Analogy
A bead thermistor is like a tiny electrical thermometer: temperature changes its electrical behavior, and the system reads that change.
Intuition Check
Do not think of “bead” as a separate moving part. Here it mainly describes the sensor’s small rounded shape.
Example Sentence 1
The outside air temperature probe uses a bead thermistor to send accurate readings to the cockpit gauge.
Example Sentence 2
Maintenance replaced the bead thermistor in the temperature probe after it gave erratic readings.