Which sensor provides an electrical signal related to its temperature?

• A. Temperature Sensor
• B. Pressure Sensor
• C. Rain Sensor
• D. Humidity Sensor

Answer: (A)

This question hinges on how sensors translate a physical property into an electrical signal, specifically which one changes its output in response to temperature. A temperature sensor is designed to do just that: its electrical signal varies as temperature changes. Devices like resistance temperature detectors (RTDs) and thermistors change their resistance with temperature, yielding a signal—often converted to voltage or current—that tracks temperature. Thermocouples generate a small voltage that depends on the temperature difference between two junctions, directly tying the electrical output to temperature.

Other sensors here measure different quantities. A pressure sensor converts pressure into an electrical signal via a diaphragm and strain gauge, a rain sensor detects moisture on a surface, and a humidity sensor measures ambient moisture, typically by changes in capacitance or resistance. None of those outputs are inherently tied to temperature in the way a dedicated temperature sensor’s output is.