Question

With a neat diagram explain the working of a magnetron.

Answer 1

It is a diode usually of cylindrical configuration with a thick cylindrical cathode at the center and a coaxial cylindrical block of copper as anode. In the anode block are cut a number of holes and slots which act as resonant anode cavities. The space between the anode and cathode is the interaction space and to one of the cavities is connected a coaxial line or waveguide for extracting the output.
It is a cross field device as the electric field between anode and cathode is radial whereas the magnetic field produced by a permanent magnet is axial. The permanent magnet is placed such that the magnetic lines are parallel to the vertical cathode and perpendicular to the electric field between cathode and anode