(under subclass 148) Subject matter wherein the converter includes an electronic tube.
(1) Note. See the class definition, Glossary for a definition of an electronic tube.
SEE OR SEARCH THIS CLASS, SUBCLASS:
111+, for current conversion systems having an electronic tube converter.
166+, for frequency conversion systems having an electronic tube-type converter.
SEE OR SEARCH CLASS
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, appropriate subclasses for miscellaneous electron tube systems not otherwise classified.
