NEGATIVE RESISTANCE OR REACTANCE NETWORKS OF THE ACTIVETYPE:
(under the class definition) Systems including active elements for producing, across at least two of the system terminals, a negative resistance and/or an inductance or capacitance which may be positive or negative.
(1) Note. This subclass does not include dynamoelectric machine systems which are used as a reactance element.
SEE OR SEARCH CLASS
307, Electrical Transmission or Interconnection Systems,
401+, for nonlinear reactance systems which may exhibit negative resistance characteristics.
323, Electricity: Power Supply or Regulation Systems,
212, 219 for phase shift systems. 327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, appropriate subclasses for miscellaneous circuits utilizing negative resistance devices.
330, Amplifiers,
75+, for feedback amplifiers of the vacuum, tube type, particularly subclasses 82, 93, 101, 104, and 112 for positive feedback amplifiers; and subclasses 291+ for transistor feedback amplifiers.
331, Oscillators,
86+, for magnetron-type oscillators which may utilize negative resistance effects; subclass 115 for transistor oscillators of the negative resistance type; subclasses 126+ for oscillators utilizing the negative resistance characteristic of a gaseous space discharge; and subclasses 132+ for negative resistance or negative transconductance oscillators in general. Subclasses 1+ of Class 331 provide for automatic frequency stabilized oscillators many of which utilize adjustable reactance tubes, indented subclass 36 provides for particular frequency control means (e.g., reactance tubes, saturable inductors, etc.); and subclass 180 provides for oscillators in general including frequency adjusting means of the reactance tube type.
332, Modulators, particularly
140, and 142+ for reactance tubes in frequency modulators, subclasses 147+ for reactance tubes in phase modulators, and subclass 175 for reactance tubes in amplitude modulators.
334, Tuners,
14+, for tuners utilizing reactance tube networks.
