REFLEX OSCILLATORS 



671 



would probably not fill the whole tube, and the effect of transverse fields 

 would be less. ■ i • 



Perhaps a more useful expression is one involving longitudinal fields 

 only; that for infinitely fine parallel grids. In this case, if the separation 



is ^ 



^' = sin^' iy(/2)/{yt/2y 



(h55) 



and, from (h43) 



2Fo (t^/2) L (t^/2) ' ' J 



In Fig. 140, (GVo/Io) is plotted vs (yC/2). The negative conductance 

 region beyond yt - 2x, familiar through Llewellyn's work with diode 

 oscillators, is of less interest in connection with reflex oscillators. 



0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 



GRID SEPARATION, 7l, IN RADIANS 



Fig. 140. — Gap loading factor for fine parallel grids vs grid separation in radians. 



. It is of some interest to compare the electronic gap loading with the small 

 signal electronic conductance due to drift action. Assume, for instance, 

 we have fine parallel plane grids for which yf=ir. From (h2) we get 



(GVo/h) = .202. 



As the current crosses the gap twice we should count the current involved 

 as twice the d-c beam current /& 



From (2.1) 



G = .404 h/Vo 



^ = .633 

 /3^ = .400. 



