(under subclass 204) Subject matter wherein power supply, bias means or isolating means are supplied to the filamentary cathode of the vacuum tube amplifying device, as input electrode; and/or as cathode heating electrical current supply to the directly heated filamentary cathode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
115, for amplifiers having unrectified A.C. power supplied to a filamentary cathode.
127, for control of emission of a cathode electrode.
201, for power supply bias means for cathode filaments in a plural stage amplifier heated by the anode current or by current from the anode supply source.
206, for power supply for a filamentary cathode generally.
SEE OR SEARCH CLASS 315, Electric Lamp and Discharge Devices: Systems,
94+, for power supply or power supply circuit for cathode filament or cathode heater circuit with or without anode supply but not including grid biasing supply.
