. American telephone practice . A piece of hard rubber projects between the two bind-ing posts of the instrument as shown, the object of this being toprevent the tips of the receiver cords from twisting the posts intheir sockets until they touch each other, thus short-circuiting theinstrument. This receiver is well made, handsome, and receiver shown in Fig. 33, manufactured by W. J. Murdock, THE TELEPHONE RECEIVER. 47 Chelsea, Mass., embodies a decidedly novel feature. In this all theworking parts of the receiver, including the permanent horse-shoemagnet, the pole-pieces, the bin
. American telephone practice . A piece of hard rubber projects between the two bind-ing posts of the instrument as shown, the object of this being toprevent the tips of the receiver cords from twisting the posts intheir sockets until they touch each other, thus short-circuiting theinstrument. This receiver is well made, handsome, and receiver shown in Fig. 33, manufactured by W. J. Murdock, THE TELEPHONE RECEIVER. 47 Chelsea, Mass., embodies a decidedly novel feature. In this all theworking parts of the receiver, including the permanent horse-shoemagnet, the pole-pieces, the binding posts and the leading-in wires,are moulded in a shell so as to form one integral part. The dia-phragm is held in place by the ordinary ear-piece, which screws inplace as in other receivers. The coils slip bn over the pole-pieces,this being the only way of replacing a coil in case of a burn-out orinjury without destroying the shell itself. It has now been on themarket for over a year and is apparently giving FIG. 34,—PARTS OF WATCH-CASE RECEIVER. The diaphragms used for receivers are made of very soft thinsheet iron; the ferrotype plate formerly used for tin-types in pho-tography being as good material as can be found for this companies, however, are using tinned-iron diaphragms, whichgive equally good results. The diaphragms for the various receivers here described varyfrom 2 to 2\ inches in diameter, the free portions—that is, the por-tions not clamped by the supports—ranging from i \ to 2 usual thickness is from .009 to .on of an inch. The thickness 43 AMERICAN TELEFHOXE PRACTICE. of a diaphragm, to produce the best results with a given receiver,must be obtained by experiment, as it depends on the diameter ofthe portion free to vibrate, and also on the strength of the magneticfield, due to the permanent magnet. It has been shown that witha very thin diaphragm and a very powerful magnet the iron in thediaphragm becomes saturate
Size: 2022px × 1235px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookdecade1900, bookidamericantelepho00mill
