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647 



which causes the increase in rectified current, and not the effect of 

 transit angle directly. 



Part IV — Negative Grid Triodes 

 The general aspect of the negative grid triode is shown in Fig. 1. 

 The upper diagram shows a plan view of the electrode arrangement and 



1- 



ic 



-Xc- 

 TC 



B 



I 



I 



■r 



I 



-\- 



I o I 



2 



l^-H 



Va = Vg (NEARLY) 



vc 



Fig. 1. — Nomenclature and potential distribution in negative grid triodes. 



indicates the nomenclature which will be adopted. The planes at Vc 

 and Vp constitute the cathode and plate, respectively, and the grid 

 wires are indicated by the small circles. The planes A and B are 

 imaginary planes located on opposite sides of the grid and only far 

 enough away so that the irregularities in the potential distribution 

 caused by the individual negative grid wires have practically disap- 

 peared. An analysis of the potential distribution in the immediate 

 neighborhood of a shielding screen has been made by Maxwell (Treatise 

 on Electricity and Magnetism Vol. I) and this applies to the grid of the 

 triode in the absence of electron flow. The presence of electrons 

 between the negative grid wires will tend to decrease the irregularities 

 shown in Maxwell's analysis and therefore allow the planes A and B 

 to be placed somewhat closer together than his figures would indicate. 

 As far as the writer is aware, exact relations for the potential distri- 

 bution near the grid wires in the presence of electron flow have not been 



