KENNELLY AND PIERCE. 



TELEPHONE RECEIVERS. 



135 



tlie vector for any given frequency is the cord of a circle through the 

 point. As the angular velocity of the impressed e. m. f . increases from 

 zero to infinity, the free end of the vector impedance passes once around 

 the circle. Circular graphs of this character are plotted in Figures 

 7 to 11 for different instruments or for different values of impressed 



Figure 8. Circular graph for bipolar Bell receiver R^ with 0.42 volt at 

 terminals. Diameter 103.5 ohms. Depression angle (2/3), 73°; «o = 4940 

 radians per second; a = 200. Small circles observed. Internal ring num- 

 bers computed. 



e. m. f. These several circular graphs are on different scales, and are 

 summarized to the same scale in Figure 12. 



On each of the circular graphs, all of the observed points, for a given 

 receiver with a given impressed e. m. f., are plotted as small circles. 

 The measured angular velocities of the impressed e. m. f. for the 

 observed points are printed at the outside of the circular locus. To 

 avoid crowding, not all of the points are designated with angular veloci- 

 ties, and in the selection of the points to bear numerical designation of 

 angular xelocity, those points were chosen, for which the measure- 

 ments were made with especial precaution as to voltage and frequency. 



The numbers placed ijiside of each of the circular loci are computed 

 values for the theoretical distribution of angular velocities around 



