DIFF Subgroup
H03F 3/55 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 > Amplifiers using transit-time effect in tubes or semiconductor devices > with semiconductor devices only
CPC:
Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements > Amplifiers using transit-time effect in tubes or semiconductor devices (parametric amplifiers H03F7/00; solid state travelling-wave devices H10N70/10) > with semiconductor devices only
No child classifications to compare. This is a leaf node in both IPC and CPC.