THEORY OF MULTI-ELECTRODE VACUUM TUBES 



79 



In Fig. 19, a more extended family of characteristics is shown for a 

 positive-net potential of 65 volts. Across these static characteristics a 

 dynamic load characteristic is drawn for a resistance load of 3400 ohms, 

 which matches the plate resistance of the tube at the operating point 



50 



ili 40 



a. 



5 30 



z 



z 

 y 20 



-120 



r 

 f 



■ too 

 I 



• 80 



; 60 



I 



40 



-130 -120 -110 -100 -90 -80 -70 -60 -60 -40 -30 -20 

 CONTROL-GRID VOLTAGE, Eg 



-10 



10 



Fig. 18 — Plate current-control grid voltage characteristics of a co-planar-grid 

 tube with various values of plate voltage and net (positive-grid) voltage as param- 

 eters. 



P. At this point £p = 130 volts, £„ = -f 65 volts, Eg ^ - 51 volts, 

 /p = 35 milliamperes, and m = 5.3. The turning over of the dynamic 

 characteristic at the top is due to the increasing fraction of the total 



