Oscillation-Hysteresis in Simple Triode Generators. 189 



of B may be most easily varied in a practical case by means 

 of a variation of C the capacity, or E. the resistance of the 

 oscillatory circuit. A cycle of the type indicated in fig. 5 

 was accordingly carried out for a circuit of the type shown 

 in fig. 1, A, the amplitude of the oscillations being indicated 

 by means of a crystal detector and galvanometer connected 

 in series with a coil which was loosely coupled with the 

 oscillator circuit. Fig. 6 shows the relation obtained between 

 the galvanometer deflexion and the value of R. Tlie general 

 aoreement with the theoretical curve of fig. 5 is at once 

 apparent. 



For certain types of oscillation characteristic we found 

 evidence of the possibility of two stable amplitudes of the 

 same frequency, both differing from zero for a given set of 

 circuit parameters. For example, it was sometimes found 

 that on decreasing the resistance R a small oscillation 

 started before the resistance value equivalent to B = was 

 reached. This effect is illustrated by the dotted line in 

 fio-. 6. It was also found that if the resistance was not 



Fig. 6. 



3C 



V 















! 



1 







N^ 









1 







^S 







i 1 











*°^L 







1 









t 





^>a^v^ 



i 



* 1 









*Jl i Cfc— 



_±s: — 



«_ 



<gU„ "T *— "* 



190 200 210 220 230 240 250 



/Pes/stanoe /? in oA/ns. 



allowed to become less than that represented by B = 

 (fig. 5), the relation between amplitude and resistance was 

 reversible. It is clear that two more terms are necessary 

 in the series for ^r{v). to account for this effect. We have 

 thus evidence of a phenomenon depending on the value of the 

 seventh differential coefficient of the oscillation characteristic. 



