IPC Main Group
H01J 21/00 Vacuum tubes
Introduced: September 1968
Last revised: January 2006
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC ELEMENTS
- Subclass:
- ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
Related Keywords
VACUUM tubes
4 direct subcodes
Child Classifications
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- H01J 21/02 Tubes with a single discharge path
- H01J 21/2 Tubes with more than one discharge path; Multiple tubes, e.g. double diode or triode-hexode
- H01J 21/34 Tubes with electrode system arranged or dimensioned so as to eliminate transit-time effect
- H01J 21/36 Tubes with flat electrodes, e.g. disc electrode