218 



ANNAL8 NEM' YORK ACADEMY OF SCIENCES 



An alternating E. M. F. impressed between the grid and the filament 

 causes variations in the wing current in the manner indicated in Fig. 4, 

 the positive alternation producing an increase and the negative alterna- 

 tion a decrease in the wing current. This is the action involved in the 

 audion when it is used as aii amplifier. 



lsS& 4/lA/^ 



Potential of '' 

 Grid with q 

 respect to 

 Filament - 



l/l/|/l/lA^ 



H/lMlM- 



-4M^^^^ 



c. J;Zt --fMAAA^ 



■-MAAm^— 



Te/ep/fone 

 Current 



Pig. 7 



Fig. 8 



To substantiate the above and other actions, the writer, working in 

 conjunction with Prof. J. H. Morecroft, of Columbia University, has 

 secured oscillograms which substantiate the idea just presented. Fig. 5 

 shows the arrangements with which the test was carried out. 



OscflZ'fions -lil/l/lAAA^ 



TJj/jfj/l/lM/ 



Potential 

 of Grid n 

 with " 

 respect to 

 Filament 



Wing 

 Current 



— \f\!\{W^^^ 



-o\j\/\/W^ 



Telephone 

 Current 



Fig. 



The potentiometer F was used to adjust the grid to a potential corre- 

 sponding to point F at the center of the operating part of the curve 

 shown in Fig. 1. The audion is capable of handling the greatest amount 



