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ID = 77747
United States of America (USA)
Brand: Amperex; New York
Developer: Amperex; New York 
Tube type:  SPECIAL TUBE, other or unknown 
  Ca. 1925 up to 1945 very rare. ***
Identical to C-100D
Similar Tubes
Heater different:
Predecessor Tubes C-100A  

Base 6-Pin-Base U6A, old, USA
Was used by Transmittertube (Radio)
Filament Vf 2.5 Volts / If 2.25 Ampere / Direct

Negative resistance oscillator tube specifically developed for Collins by Amperex, to avoid to be sued for patent infringement by RCA, AT&T, Westinghouse and the other owners of the rights for the De Forest triode oscillator circuit. The tube was intended for use in crystal controlled transmitters.

It derived from C-100A, with a different internal structure for better sensitivity. The negative electrode, equivalent to the grid, surrounds a finned positive electrode.

Very few tubes were made before the settlement with RCA and the subsequent use of a 6L6 as conventional oscillator.

Information source -- Original-techn. papers.   
  C-100D: Manufacturer's Literature
Emilio Ciardiello
C-100D: Private collection
Emilio Ciardiello


from Just Qvigstad

Documents about this component
  Short form catalog of Collins tubes 157 KB

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