Electrical contact thermometers are devices that control temperature via electrical contacts, operating on principles of temperature sensing and circuit control. When the temperature reaches a preset value, the contacts close or open, triggering or stopping heating/cooling equipment. Inside these thermometers, a temperature sensing element (such as a bimetallic strip or thermocouple) changes shape or generates voltage variations upon temperature change, thus actuating the electrical contacts. These devices find wide application in industrial automation, HVAC systems, food processing, and more, known for fast response, high precision, and reliability. Key components include the temperature sensing element, electrical contacts, and control circuits, working together to sense temperature changes and transmit action signals to external devices.