446 THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1952 



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Fig. 1 — Cold-cathode gas tubes — pentode, diode and octode. 



of such a system. System operation is described in this paper after a 

 more detailed discussion of the components mentioned above. 



COMPONENTS 



Cold cathode tubes, usually diode or triode types, have found wide- 

 spread application in the past but the gas tubes used in the ECASS 

 system were developed to have special characteristics for switching use. 

 The three types of cold cathode gas tubes used were: a diode, a screen 

 grid pentode and a multi-purpose octode. Fig. 1 shows a photograph of 

 each type and Fig. 2 gives a schematic drawing of the internal elements. 

 These tubes were developed by W. A. Depp and R. L. Vance. The diode 



ANODE 



MAIN ANODE 



MAIN ANODE 



CATHODE 



A- 1627 

 DIODE 



SCREEN , . 



GRID Pf^- 



STAR' 

 CATHODE 



Fig. 2 — Schematics of cold-cathode gas tubes. 



