Oscillation-Hysteresis in Simple Iriode Generators. 185 



3, 4, and 6 of" the table have been drawn in fig. 2, where the 

 possible amplitudes have also been indicated. 



Fig. 2. 



No. 2. 



No. 4. 



No. 3. 



No. 6. 



For any amplitude to be stationary, it follows from energy 

 considerations that the damping term for a cycle of v must 

 be partially positive and partially negative. In this way we 

 see that the amplitudes a 2 and a 3 are possible. In order that 

 the amplitude should be stable, however, it is necessary that, 



if the amplitude of v increases, the damping fact 



or 



civ 



should be positive over a greater part of the cycle of v and 

 vice versa. Thus a 2 is stable in Nos. 2, 3, and 4 but not in 

 No. 6. In the same way a 3 is stable in No. 6 but not in No. 3. 



In fig. 2 the function y has been made symmetrical 



with respect to the axis v=0, since from (9) and (10) it is 

 seen that, so far as our present approximations go, the even 

 terms (e. g. } /3, 8, etc.) of the series for the oscillation 

 characteristic can be neglected. We may obtain a derived 



