204917 ⎘
Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons; Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators; Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone in which the electron stream is perpendicular to the axis of the resonator or resonators and is pencil-like before reflection