What is the temperature sensitive resistor used to monitor seat temperature called?

• A. RTD
• B. Thermopile
• C. Thermistor
• D. Thermocouple

Answer: (C)

A device that changes its resistance with temperature and is used to sense heat is a thermistor. In car seats, thermistors—usually of the NTC type—are favored because their resistance drops noticeably as temperature rises, giving a strong, compact, inexpensive sensor that works well over the typical seat-temperature range (roughly in the lower to mid tens of degrees Celsius up to body temperature). This makes it easy to embed in the cushion and to feed a precise signal to the climate or seat control system.

RTDs are also temperature-sensitive resistors, but they use metals and provide very linear, precise readings, which makes them larger, more expensive, and less sensitive in the narrow seat-temperature range. They’re less common for seat sensing. The other two options, thermopiles and thermocouples, generate voltage signals from temperature differences rather than changing resistance, so they’re not “temperature sensitive resistors.” That’s why they don’t fit the description for a seat temperature sensor.