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BELL SYSTEM TECHNICAL JOURNAL 



graphically, showing both phase and magnitude, and this paper is referred 

 to for details. 



Tables I, II and III, in conjunction with Figs. 8, 13 and 15, allow us to 

 derive the equivalent networks of Figs. 19, 20 and 21. 



We must now undertake a discussion of the results given in the tables as 

 well as of the networks which were derived from them. 



(a) 



y2t 



yn y22 



(b) 



(c) 



k = 



y2i 



y.a.^ 



Vz 



Fig. 19 (a, b, c) — Three forms of equivalent circuits of the grounded cathode triode 

 valid at all frequencies. 



Initially, it is well to emphasize again that the four-pole parameters and 

 the corresponding networks are different but equivalent ways through which 

 the triode signal behavior becomes completely specified for all conditions of 

 space charge and for all frequencies. 



Secondly, there are certain general relations which should be noted. We 

 observe, first, that the determinants A^ and Az are invariants for the dif- 

 ferent modes of triode operation, and with exception of phase reversals this 



^Loc. cit. 



