The defrost cycle is a process used in refrigeration systems, such as refrigerators and freezers, to remove frost buildup from the evaporator coils. Frost can accumulate when moisture in the air freezes on the coils, reducing efficiency. During the defrost cycle, the system temporarily stops cooling and uses heat to melt the frost, allowing it to drain away. This cycle typically occurs automatically at regular intervals, depending on the design of the appliance. Some systems use a timer, while others rely on sensors to detect frost levels. Efficient defrosting helps maintain optimal performance and energy efficiency in refrigeration units.