Thermal sensor

Also known as temperature sensors. These are used to sense the temperature state of an subject via contact or non-contact sensing. Contact sensors typically are adhered to the object to directly read their temperature. Non-contact sensors are placed near the subject, these are useful when the object would be too hot to touch or, the subject is a fluid. These sensors typically provide a resistive value or act as a switch.

References:

https://www.sciencedirect.com/topics/engineering/thermal-sensor

https://www.watelectronics.com/thermal-sensor/