Microwave is an electromagnetic wave. A microwave oven consists of a power supply, a magnetron, a control circuit, and a cooking chamber. The power supply provides a high voltage of approximately 4000 volts to the magnetron. Under the excitation of the power supply, the magnetron continuously generates microwaves, which are then coupled into the cooking chamber through a waveguide system. Near the inlet of the cooking chamber, there is a rotatable stirrer. As the stirrer is a fan shaped metal, it reflects microwaves in various directions when it is turned on, so it can evenly distribute microwave energy in the cooking chamber and heat food. The power range of a microwave oven is generally between 500 and 1000 watts.