(under the class definition) Subject matter wherein the amplifying device is a vacuum tube provided with means to form the electric space discharge into a restricted beam or ray, usually pencil-like.
(1) Note. Means to control the electron trajectory of the electrons emitted from the cathode (as in magnetrons which are classified below) is not regarded as an electron beam forming means required for classification in this and indented subclasses.
(2) Note. Subject matter broadly claiming so-called "beam power tubes" are not classified in this subclass but are classified below in the appropriate subclass for the circuit involved.
SEE OR SEARCH THIS CLASS, SUBCLASS:
42, for amplifiers having secondary electron emission tube amplifying devices.
43, for amplifiers having traveling wave type amplifying devices.
47, for magnetrons. 308, for amplifiers including an electron beam forming means and a semiconductor element as a target means therein.
SEE OR SEARCH CLASS
313, Electric Lamp and Discharge Devices,
364+, for cathode-ray tubes, per se. See the search notes of Class 313.
315, Electric Lamp and Discharge Devices: Systems,
1+, for cathode- ray tubes with means to supply electric current or potential thereto and/or cathode ray tubes structurally combined with a circuit element. See the search notes of Class 315.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems,
600, for miscellaneous circuits having a particular beam tube structure.
329, Demodulators, appropriate subclasses and particularly
368, for an amplitude demodulator employing an electron discharge device of three or more electrodes.
