MEASUREMENTS AT TELEPHONIC FREQUENCIES. 105 



All of the circles of constant resistance have their centers on the 

 line OR, or axis of reals. 





i^o 



}^ 



V5 



-^10 



7^5 



Fig. 5. Graphs of vector current or vector admittance for a RLC circuit, in 

 which either i? or C is varied alone. 



In Fig. 5, the full lines are the theoretical loci and the small cir- 

 cles the actual potentiometer readings. Fig. 6 is obtained by inver- 



