Magnetron

Magnetron is a special tube for high power microwave generation with good efficiency. It is a vacuum diode placed in the field of a strong magnet. Because of the magnetic field, the electrons start to follow a circular path. The wall of the vacuum chamber contains cavities in which a microwave oscillation is induced by the flow of the electrons. The principle is similar to the howling sound created by blowing on a bottle. Even a small magnetron can have impulse power in tens of kW. Since World War II, it was used in radars. The successful development of magnetron had a great impact on the quality of British air radars which could be made so small that they could fit inside an airplane. The German radar technology, based on klystrons, did not enable this. All of this made a contribution to the victory of the Allies in the air war. Today, magnetrons are used mainly in microwave ovens where they serve as a simple, cheap and reliable source of microwave power.