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An electron tube that produces coherent microwave radiation. Magnetrons are diodes in which the electrons traveling to the anode are set in spiraling paths by a magnetic field created by permanent magnets. The circular component of the electrons' motion causes microwave-frequency oscillations in the voltage induced in resonating cavities built into the anode, which is connected to an antenna that emits the microwaves. Magnetrons are used in radar and in microwave ovens.
diode vacuum tube consisting of a cylindrical (straight wire) cathode and a coaxial anode, between which a dc (direct current) potential creates an electric field. A magnetic field is applied longitudinally by an external magnet. Connected to a resonant line, it can act as an oscillator. Magnetrons are capable of generating extremely high frequencies and also short bursts of very high power. They are an important source of power in radar systems and in microwave ovens.