DIFF Subgroup
H03F 3/21 with semiconductor devices only
Introduced: July 1974
Full Title
Full titles differ between systems:
IPC:
Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements > Power amplifiers, e.g. Class B amplifiers, Class C amplifiers > with semiconductor devices only
CPC:
Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements > Power amplifiers, e.g. Class B amplifiers, Class C amplifiers (H03F3/26 - H03F3/30 take precedence) > with semiconductor devices only
Of 3 combined children, 2 exist in both systems.
1 codes are CPC-only extensions.
IPC defines codes here since 1974.
Child Classifications
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- H03F 3/217 Class D power amplifiers; Switching amplifiers since 1974 +5 CPC IPC+CPC Available in IPC and CPC