AN IMPROVED TELEPHONE SET 



255 



<n 10 



5 



LU 

 Q 



1 

 UJ 



a. 



200 400 600 1000 2000 4000 6000 10,000 



FREQUENCY IN CYCLES PER SECOND 



BACK CHAMBER, Sb--^ 



HOLE IN DIAPHRAGM, - 

 Rh Mh 



CAP GRID HOLES, — ■- 

 RqMg 



GRID-MEMBRANE— ~--^-__fci 

 CHAMBER, Sg -^-^5 



MEMBRANE, Rm Mm -|_ p 



llP'^"l 



CARBON- Sc Mc Rc" 



MEMBRANE-DIAPHRAGM 

 CHAMBER, Sm ■•"' 



RIBBED DIAPHRAGM. 

 Md2 1^02 ^02 ^^ 



ACOUSTIC RESISTANCE ^■^;^^v.■•.■•^?^-^='f7t^•"••.■•■••- 

 ELEMENT, Rx My --^ l••■.•••::.••■.•.•^•••■• 

 CUP CHAMBER, Sx" 



r^G iviG iviM r^M '^'D2 "^02 , 



02 Mc 



EQUIVALENT 

 CIRCUIT 



Fig. 11— Equivalent circuit and frequency response of transmitter. 



