TELEPHONE DIAPHRAGMS. 481 



List of Symbols Employed. 



A Force factor of an electromagnetic receiver (dynes/absampere) . 



Ai "_ " "a loaded " " " 



a Radius of a circular disk, or of a diaphragm, within clamping 



circle (cm). 



a, a I a-z Phase angles whose tangents are mechanical reactance factors 



(radians or degrees). 



ab- or abs- Prefix denoting a C. G. S. magnetic unit. 



3?o Mean flux density over air-gap or gaps in receivers, due to perma- 



nent magnets (gausses). 



/3 = ^-^ — Mean phase angle of force factor. 



/3i /S-. Phase lags of force and of induced emf . (radians or degrees). 



A = r/(2m) Damping constant of a receiver diaphragm. Numeric per second. 



d Sign of differentiation. 



emf. Contraction for electromotive force. 



€x Motionally induced emf. in windings, at any instant, (abvolts Z ). 



e = 2.71828 Napierian base. 



exm M aximum cyclic value of motional emf . (abvolts) . 



F Fi F2 Maximum cyclic value of a vmf . (dynes). 



/ Frequency of alternation . (cycles per second) . 



Also vibromotive force (vmf.) on a diaphragm, (dynes Z ). 



/o Resonant frequency of alternation, (cycles per second) . 



fi Instantaneous value of a vmf. due to an alt. current i absamperes 



(dynes Z ) . 



fm Maximum cyclic value of vmf. (dynes). 



7 Angle of equiangular spiral in free oscillation, (radians or de- 



grees) . 



I Root mean square value of sinusoidal alternating current, 



(absamperes) 



Im Maximum cyclic value- of sinusoidal alt. current at resonance, 



(absamperes) . 



i Instantaneous value of sinusoidal alt. current in winding, (ab- 



samperes) . 



> .= V^T. 



kine 1 cm. per sec. (unit velocity in C. G. S. system). 



L Inductance of receiver winding damped, (abhenrys). 



Li " " " " free, (abhenrys). 



M Total active mass of diaphragm within clamping circle, (grams). 



m Equivalent mass of a diaphragm, (grams) . 



mi Massattached to the center of a diaphragm as load, (grams). 



M Symbol for 10~^ mm., or 1 micron. 



N Number of turns in winding of a receiver, including both poles, 



(numeric) . 



n Number of annuli into which a vibrating diaphragm may be sup- 



posed to be divided . (numeric) . 



Pm Maximum cyclic mechanical power in diaphragm, (abwatts or 



ergs/sec) . 



5! Permeance of magnetic circuit to alternating mmfs. (oersted)"'. 



TT = 3.14159 



R Resistance of receiver winding, diaphragm damped, (absohms 



or ohms). 



R' Resistance of receiver winding, diaphragm free (absohms or ohms). 



