CONSTANT FREQUENCY OSCILLATORS 



93 



in an oscillator whose frequency depends upon operating voltages to 

 such a small extent that temperature effects become the predominating 

 influence and special precautions must be taken in order to eliminate 



200 



o 100 



O -100 



20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 



PLATE VOLTAGE 



(a) 



^ 200 



•50 



,>-, -100 



U.-200 



0.7 0.8 0.9 1.0 I.I 



FILAMENT CURRENT IN AMPERES 



1.2 



(b) 



Fig. 20 — Performance curves of reversed feed-back oscillator with tight coupling, 



grid stabilization. 



(a) Variation of frequency with plate potential. 



(b) Variation of frequency with filament current. 



them before data showing the dependence of frequency on operating 

 voltages can be obtained. 



For instance, the data for the curves shown in the accompanying 

 Figs. 20 and 21 were secured by the following procedure: A plate 



