Microwave is an electromagnetic wave. Microwave oven consists of power supply, magnetron, control circuit and cooking cavity. The power supply provides a high voltage of about 4000 volts to the magnetron. Under the excitation of the power supply, the magnetron continuously generates microwaves, which are coupled into the cooking cavity through the waveguide system. There is a rotatable agitator near the entrance of the cooking cavity. Because the agitator is a fan-shaped metal, it can reflect microwaves in all directions after rotating, so it can evenly distribute microwave energy in the cooking cavity, thus heating food. The power range of microwave oven is generally 500 ~1000 watt.