Final answer:
Electronic expansion valves sense the line temperature using temperature sensors or thermistors, which convert temperature changes into electrical signals. These signals are used to control the valve and regulate the refrigerant flow in a cooling or heating system.
Step-by-step explanation:
Electronic expansion valves sense the line temperature using temperature sensors or thermistors. These sensors are designed to detect changes in temperature and convert them into electrical signals. The signals are then used to control the opening and closing of the valve, allowing for precise regulation of the refrigerant flow in a cooling or heating system.