KENNELLY AND PIERCE. 



TELEPHONE RECEIVERS. 



139 



in which 



X = the displacement of the effective mass of the diaphragm from its 

 position of rest (cm.), 



X = the displacement velocity (cm/sec), 



X = the displacement acceleration (cm/sec^), 



s = the elastic force per unit" displacement (dynes /cm), 



r = the resisting force per unit velocity (dynes per cm. per sec.) 



/ = Fe^"', the impressed moving force measured in the direction of x 

 toward the poles (dynes), 



0) = 2t n, the angular velocity of the impressed force (radians per 

 second), and 



n = the frequency of the impressed sinusoidal force (cycles per 

 second). 



l-x 



"V- 



1^ 



.X/2_ 



-Q 



l-x 

 C3- 



r^ 



?1-^ 



\ 



-□ 



Figure 13. Diagram of receivers. A^ is number of turns. F is force on 

 diaphragm with direction of arrow; I is normal gap length; and x displace- 

 ment toward poles. 



The solution of equation (5) for velocity of displacement, after a 



steady state has been attained, is well known, and may be written in 



the form 



/ f FeJ'^^ 



- - — cm /sec Z (6) 



X = 



r + j mco— 



in which 



CO 



z = r -{- j[ viio 



CO 



dyne sec /cm Z (7) 



The quantity 2 may be called "vector mechanical impedance" from 

 its analogy to vector electrical impedance. 



