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ID = 50756
United States of America (USA)
Brand: Moorhead Laboratories (Pacific); San Francisco
Developer: Moorhead Laboratories (Pacific); San Francisco 
Tube type:  Gas Triode   Detector 
  <1925 very rare. ***
Identical to Moorhead_Ext_Grid
First year Sep.1916 Saga of the Vacuum Tube, Tyne page 168 and 169.
Predecessor Tubes ER_Moorhead  

Base Wires
Was used by Radio/TV-reception etc.
Filament Vf 4 Volts / If 1.5 Ampere / Direct / Battery =

The External Grid Moorhead was an attempt to circumvent the DeForest Triode patent. It was first advertised in the Electrical Experimenter, September 1916. Performance of this type was inferior to the standard design. This was the first Moorhead tube to be marked. There are two versions: The External Grid (made of strong stamped brass gauze) tube normally has a thick plate with Moorhead markings, but some have been seen with a thin unmarked plate.
The tube is double ended. and has a single filament.

Information source Saga of the Vacuum Tube, Tyne   Page 168
-- Collector info (Sammler)   

Collection of



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