436 BELL SYSTEM TECHNICAL JOURNAL 



Comparison of (7) and (9) shows that while /x is equal to minus the 

 ratio of the increments of Ep and Eg necessary to maintain the plate 

 current constant, v is equal to minus the ratio of the increments of 

 Ep and E^ necessary to maintain the grid current constant. On the 

 other hand, while in the case of /x, the ratio 



dEp 

 dEg 



]. 



is intrinsically negative and occurs in (7) with a negative sign, making 

 /i intrinsicalK' a posilixe number; in the case of v, the ratio 



dEp'^ 

 dEg Jig 



is usually intrinsically positive, and occurs in (9) with a negative 

 sign; hence v is usually intrinsically a negative number. 



With the foregoing dehnition, the 7"s may be written as follows: 



(10) 



:(t) 



\_yj_ 



rgdEg 



dEg\ V ) ' r, a£^V .' / "2-2 



vYn ?)Eo \ V ) r„ dEh \ V J 



where r/ = -^ • 



' dEg 



The effective value of To, when taken over a cycle of sine wave 

 form, has sometimes been called the reflex mutual conductance 

 (L. A. Hazeltine), and has been denoted by g„. An attempt to adapt 

 this notation to the present purpose has not proved feasible. P'or 

 reference, it may be noted in the limiting case, where the amplitude 

 of the sine wave approaches zero: 



1 



gn= 



UKg 



With the relations gixcn thus far. the probk-m ma>- now be more 

 specifically stated as follows: 



It is desired to express ip, the output current through a general 



