506 



BELL SYSTEM TECHNICAL JOURNAL 



correspond respectively to a conductance aiding and bucking the conduct- 

 ance arising on the first return. In case 1 we have 



^, /2/i(C2F) 



(8.13) 



2Jl(CiV) 



Ge - ye Ky 



5 



y ^e - ye C2V 



AMPLITUDE OF OSCILLATION. V 



Fig. 28. — Theoretically derived variation of electronic conductance with amplitude o^ 

 oscillation. Curve Ge represents conductance arising from drift action in the repeller 

 space. Curve Gi represents the conductance arising from continuing drift in the cathode 

 region. G" represents the conductance variation with amplitude which will result if 

 Ge and Ge are in phase opposition. 



and case 2 



^, , /2/i(C2F) 

 C2 V 



(8.14) 



Figure 28 illustrates case (2) and Fig. 29 case (1). If cos M , and cos 16 

 varied in the same way with repeller voltage, the resultant limiting function 

 would shrink without change in form as the repeller voltage was varied, 

 and it is apparent that Fig. 28 would then yield the conditions for hysteresis 

 and Fig. 29 would result in conditions for a continuous characteristic. 

 If Fig. 28 applied we should e.xpcct hysteresis symmetrical about the opti- 

 mum repeller voltage. We recall, however, that in Fig. 27 hysteresis 



