Identifier: belltelephonemag12amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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Figure 5. Still Another Alternative Arr.\ngemeni Is Provided by the 12ACarrying Case Which Assembles the Complete 38A Altdiphgne and Battery inA Single Unit. DEVELOPMENT OF THE WESTERN ELECTRIC AUDIPHONE a copper diaphragm of similar dimensions through an air cou-pling formed by the narrow air space between the two. Thecopper diaphragm acts on the granular carbon as does thediaphragm of a transmitter, and produces the desired ampli-fication. The amount of amplification can be adjusted by arheostat in the circuit. The final step in transmission, from receiver to ear, is ac-complished by the earpiece, which is made so that it can berigidly attached to the receiver and closely fitted into the ear.Of the three types available, shown in Figure 2, one is indi-vidually moulded to fit the ear of a single user, and the othersare universal types. The older universal earpiece, of hardrubber, is made in four sizes and can be adjusted to fit theimportant dimensions of any users ear. The new univer

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