IPC Subgroup
H01J 19/04 Thermionic cathodes
Introduced: September 1968
Last revised: January 2006
Full Title
Details of vacuum tubes of the types covered by group > Electron-emitting electrodes; Cathodes > Thermionic cathodes
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC ELEMENTS
- Subclass:
- ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
4 direct subcodes
Child Classifications
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- H01J 19/06 characterised by the material
- H01J 19/08 Cathodes heated directly by an electric current
- H01J 19/1 characterised by the shape
- H01J 19/14 Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment