DIFF Subgroup
H01J 19/08 Cathodes heated directly by an electric current
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Details of vacuum tubes of the types covered by group > Electron-emitting electrodes; Cathodes > Thermionic cathodes > Cathodes heated directly by an electric current
CPC:
Details of vacuum tubes of the types covered by group H01J21/00 > Electron-emitting electrodes; Cathodes > Thermionic cathodes > Cathodes heated directly by an electric current
No child classifications to compare. This is a leaf node in both IPC and CPC.