RMA Tube Designation - Famous Types

Famous Types

Many of the "1A21" series are well known to collectors and restorers of WW2 vintage radio equipment. A short list of well-known or historic types numbered under this system:

• 1N23--Silicon point contact diode used in early radar mixers.
• 1P25--Infrared image converter used in WW2 night vision "sniperscopes".
• 2C39--"Oilcan" type planar triode.
• 2C43--"Lighthouse" type planar triode.
• 2D21--Miniature glass tetrode thyratron used in jukeboxes and computer equipment.
• 2P23--Early image orthicon TV camera tube.
• 3B28--Xenon half wave rectifier--ruggedized replacement for mercury vapor type 866.
• 3E29--Dual beam power tube used in radar equipment--a pulse rated variant of the earlier 829B.
• 4D21--VHF beam tetrode better known by Eimac commercial number 4-125A.
• 5C22--Hydrogen thyratron for radar modulators.
• 6C21--Triode radar modulator for "hard tube" pulsers.
• 8D21--Internally water cooled dual tetrode used in early VHF TV transmitters.

This numbering system was abandoned in 1944 in favor of a non-descriptive numbering system of 4 digit numbers beginning with 5500. This new system persisted until the final days of tubes, with type numbers registered up into the 9000 series.