VACUUM TUBE ELECTRONICS 



+ iU' -f-cothr + f) + hf^], 

 and the R — X diagram is shown in Fig. 16. 



95 



(64) 



RESISTANCE 

 -t 



0.2 







-0.2 



-0.4 



-0.6 



-0.8 



-1.0 



-1.2 



-1.4 



<J -1.6 



I -1.8 

 (J 



^-2.0 

 -2.2 

 -2.4 

 -2.6 

 -2.8 

 -3.0 

 -3.2 

 -3.4 

 -3.6 



Fig. 15 — i?o — A'o diagram 

 for positive grid, slightly 

 positive plate triode, with- 

 out cathode space charge. 



Curve A, r} = ^ 

 Curve B,-n = l/2f 

 Curve C, Tj = l/3f 



Fig. 16 — Ro — A'o diagram 

 for positive grid, slightly 

 negative plate triode, with- 

 out cathode space charge. 



Curve A, 7) = ^ 

 Curve B,-n = l/2f 

 Curve C, r; = l/3f 



Inspection of Figs. 15 and 16 shows that the negative plate condi- 

 tion is greatly to be preferred when there is no cathode space charge. 

 In fact, when account is taken of the difference in the scales for which 

 Fig. 16 and the other three figures, 11, 14, and 15, are plotted, it is 

 evident that the negative plate without space charge offers the greatest 

 latitude in the adjustment of circuit condition. As in all of the cases, 

 except Fig. 15, a small grid capture fraction is to be desired. If 



