38 



BELL SYSTEM TECHNICAL JOURNAL 



40 80 120 160 200 240 280 320 360 

 DEGREES 



Fig. 7 — Variation of K with period of flow for curves of Fig. 6. 



100 80 60 40 20 20 40 60 80 100 

 DEGREES 



Fig. 8 — Three typical shapes of plate current for 180° flow. A, unsaturated. B, 

 slightly saturated. C, extremely saturated. 



