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Information - Help 
ID = 10555
United States of America (USA)
Brand: Common type USA tube/semicond.
Developer: Hytron; Salem (MA) 
Tube type:  Beam Power Tube   Text 
Identical to 3D21A = CV2659 = 5B/152D
Similar Tubes
Other shape (e.g. bulb type):
First Source (s)
30.Sep.1957 : Electron Tube Registration List 2017
Predecessor Tubes 3D21  
Successor Tubes 3D21B  

Base Octal (Int.Octal, IO) K8A, USA 1935 (Codex=Ucf) Top contact with a cap.
Filament Vf 6.3 Volts / If 1.7 Ampere / Indirect / Specified voltage AC/DC
Description Centre-tapped heater. May also be operated at 12.6V 0.85A with the sections in series. Primarily designed as blocking oscillator, pulse modulator and deflection amplifier. Also used as high voltage series regulator.
ST-16 domed bulb. 
Dimensions (WHD)
incl. pins / tip
46 x 122 x mm / 1.81 x 4.80 x inch
Tube prices 2 Tube prices (visible for members only)
Information source Taschenbuch zum Röhren-Codex 1948/49   
Aldo Patriarca

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3D21A: Tabu Röhren-Codex, 1948
Anonymous 15 Collector

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3D21A: Manufacturer's Literature
Emilio Ciardiello

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from Just Qvigstad

Documents about this component
  Manufacturer's Data Sheets 584 KB

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