58 



BELL SYSTEM TECHNICAL JOURNAL 



based upon the simple theory of triodes, one would expect that families 

 of characteristics corresponding very closely with those of ordinary 

 triodes would be obtained if the total space current, or the plate current, 



2.5 



-1.5 

 < 



0.5 



-11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 +1 +2 



CONTROL GRID VOLTS, Eq 



Fig. 4— Characteristics of a screen-grid tetrode. Plate current, 7p, screen cur- 

 rent, /„ and total space current, /,, as functions of the control-grid voltage, with 

 various values of i)late voltage antl screen voltage as jiarameters. 



were plotted as functions of the control-grid voltage and screen-grid 

 voltage, with the plate maintained at any fixed potential higher than 

 the screen potential. It would be expected further that the family of 

 curves showing total space current would remain practically invariant 



