VIBRATING TELEPHONE DIAPHRAGMS. 



435 



changed, there being now two maximum motional-impedances, one 

 near 676'—', and the other near 840 ^-'. Nearly midway between 

 them (753'—'), the motional impedance almost vanishes at OB. 



/Resistance "■*<' "•?<' ■•20 -/<? ^^ /o zo 30 40 so eo 

 Fig. 14. Distorted Motional-Impedance Diagram. Large Distortion Loop. 



The amplitudes of vibration of the diaphragm, as deduced from 

 the motional-impedance diagram of Fig. 14, are shown in Fig. 15 

 with amplitude ordinates, and abscissas in impressed frequency. It 

 will be seen that the amplitude almost vanishes at 753 '-', which is 



