VIBRATING TELEPHONE DIAPHRAGMS. 459 



c^. Instantaneous emf. opposite and equal to cemf. of motion 

 (abvolts Z). 

 e = 2.71828 Base of Naperian logarithms. 



/ Instantaneous vibromotive force or torque (dynes) or (dyne- 



perp.-cm.). 

 /, Force entering into a torque (dynes). 

 !■ Maximum cyclic vibromotive force or torque, (dynes) or 



(dyne-perp.-cm.). 

 /... Maximum cyclic counter V.M.F. of absorption (dynes Z). 

 Angular deflection of vibrator mirror (radians Z). 

 dm Maximum angular deflection at resonance (radians). 

 6*0 Initial amplitude of angular deflection at moment of release 



(radians). 

 Os Steady angular deflection produced by a continuous current 



(radians). 

 6t Amplitude of angular deflection at time t after release (ra- 

 dians). 

 Complex instantaneous angular velocity (radians/sec. Z). 

 Complex instantaneous angular acceleration (radians/sec. 2 Z). 

 / A continuous current strength (absamperes). 

 Im Maximum cyclic current in the vibrator (absamperes). 

 i Complex instantaneous current strength (absamperes Z). 



/ Length of radius arm on which a torque acts (cm.). 

 m Moment of inertia of vibrating system (gm.-cm.-). Also 



mass of linear vibration system (gm.). 

 nu Mass of a secondary linear vibration system (gm.). 

 n Impressed frequency (cycles per sec). 

 ;;„ Resonant frequency (cycles per sec). 



Ml Frequency at earlier quadrantal point in motional circle (cy- 

 cles per sec). 

 H3 Frequency at later quadrantal point in motional circle (cycles 

 per sec). 

 p^r./r^ Ratio of secondary to main mechanical resistance (numeric). 



TT = 3.1416 



r Torque of resistance to angular velocity (dyne-perp.-cm. /ra- 

 dian per sec). Also resistance to vibrational motion of a 

 diaphragm (dynes/kine). 

 r. Resistance of secondary or dependent system to motion 



(dynes/kine). 

 s Torque of angular displacement (dyne-perp.-cm. /radian). 

 Also elastic constant of linear vibration system (dynes/cm.). 

 ^2 Elastic constant of secondary linear vibration system 



(dynes/cm.). 

 / Elapsed time (sees.). 

 T Torque (dyne-perp.-cm.). 

 A = w„/2A Resonant sharpness, or sharpness of tuning (numeric). 



