The V24 was designed about 1919 by Captain Round of the Marconi company. The 24 in the designation refers to the standard battery voltage then used by UK Military Services. It was designed as an RF amplifier, and worked well. To avoid instability several stages of amplification were used in cascade.
The insert picture has been enhanced to show the lettering. The valve transferred to M-OV production in about 1920 and continued to be made until the late 1930s.
The thin glass tube envelope is 18 mm in diameter and, including the base studs, is 73 mm tall.
Reference: 1003. Type V24 was first introduced¶ in 1919.
Absolute Maximum Operating Conditions¶