Sharp-Cutoff Tetrode
These are commonly called Balloon or Globe types.
The Philco Globe 24 Vacuum tube is a glass type used as
an RF amplifier or biased detector
in AC-operated receivers. It was first developed in 1930
by RCA and requires a five-contact socket.
Electrical Data:
Filament Voltage .............................. 2.5 V
Filament Current .............................. 1.75 A
Preferred Substitutes ................... 24A, 224,
UX-224A, 324, CX-324A, 35, 51