microwave oven, device that uses microwaves to rapidly cook food. The microwaves cause water molecules in the food to vibrate, producing heat, which is distributed through the food by induction. A special electron tube called a magnetron produces the microwaves. Typical output power for consumer devices ranges from 650 to 1200 watts. To ensure even heating, the magnetron directs its waves at a rotating metal disk with offset vanes, which scatters the waves through the oven cavity; a rotating platform for the food is sometimes used in addition. Power settings may reduce the amount of radiation by cycling a constant-output magnetron on and off for varying lengths of time, or may reduce the level of radiation constantly produced by an inverter magnetron. The magnetron may be supplemented by quartz and halogen bulbs for browning food, which microwaves do poorly.