A water temperature sensor is a device used to measure the temperature of water in various applications, such as automotive engines, HVAC systems, industrial machinery, and household appliances. It works by detecting temperature changes and converting them into electrical signals that can be monitored or displayed. In an engine, for example, the sensor helps ensure the water or coolant temperature remains within a safe operating range to prevent overheating. It is a critical component in systems that require precise temperature control for efficiency, safety, and performance.