What does the thermometer do in furnace control system?

In a furnace control system a thermometer, or temperature sensor, continuously measures the temperature inside the furnace. This sensor provides the controller with information about the current temperature, which is compared to the desired temperature setting. Based on the temperature reading, the controller regulates the heat output to maintain the desired temperature and achieve the desired heating or cooling effect. The thermometer plays a crucial role in maintaining the desired temperature and ensuring the efficient operation of the furnace control system.