(under subclass 114) Subject matter wherein the electrode, to which the A.C. power supply voltage is applied, is a filamentary directly heated cathode.
(1) Note. A.C. power supply for heaters of indirectly heated cathodes are not classified in this subclass but are classified in subclass 113, above, in the special case where they involve a polyphase power supply. Amplifiers with cathode filaments heated by the anode current are classified in subclass 201 of this class. Amplifiers with heater supply otherwise are classified in subclass 199.
SEE OR SEARCH CLASS
315, Electric Lamp and Discharge Devices: Systems, appropriate subclasses indented under
94, particularly subclasses 97 and 105+ for subject matter involving A.C. power supply to cathodes or cathode heaters.
