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TypeA

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ID = 28370
       
Country:
United States of America (USA)
Brand: Moorhead Laboratories (Pacific); San Francisco
Developer: Moorhead Laboratories (Pacific); San Francisco 
Tube type:  LOCKED OFF TUBE (CODE 9) - see in Notes   Universal 
  <1925 rare.
Identical to TypeA = A_Moorhead = VT-Class-II
First year Sep.1919 Saga of the Vacuumtube, Tyne page 172

Base UV-Base (4 Pins+Bayonet, USA 1914 WE)
Was used by Radio/TV-reception etc.
Filament Vf 4.5 Volts / If 0.7 Ampere / Direct / Battery =
Description Moorhead/Marconi/DF Type A: The Type A is a hard tube also known as the Marconi VT Class II. It is very similar to the SE-1444 (if not the same). Some have Class II marked on the base rather than A on the bulb. See also the spherical version. Tyne describes the drawn tungsten wire filament, the eleven-turn spiral of nickel-wire-grid and the nickel sheet plate, rolled into a cylinder about 3/4 inch in diameter. It operates for 60 to 90 volts.

Family - according to Tyne: Type A is similar to SE-1444, also with hard vacuum for amplification. Type B is a similar tube, but with a low vacuum for operation as a detector with 18-40 volts on the anode. Type C is similar to Type A, except that the grid is constructed of 22 turns of molybdenum wire with a pitch of 0.3 inch, instead of nickel - and for anode voltages of 80 - 500 volts. Type D is the unbased Electron Relay (ER) previously made by Moorhead. Type E is the British standard Type R, similar to Type A, but with spherical bulb and European standard four-pin base. Type F is similar to Type E, but with a low vacuum like the Type B. Type G is similar to Type C, but has a spherical bulb and an European standard four-pin base. It is the same as the British standard Type B tube. 
Text in other languages (may differ)
Dimensions (WHD)
incl. pins / tip
45 x 112 x mm / 1.77 x 4.41 x inch
Weight 56 g / 1.98 oz
Literature Saga of the Vacuumtube, Tyne   page 172
 
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TypeA: own collection
Peter den Boer

 

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