Wireless Telegraphy and Telephony
Forfatter: Alfred P. Morgan
År: 1917
Forlag: The Norman W. Henley Publishing Company
Sted: New York
Udgave: Third Edition, Fully Illustrated
Sider: 33
UDK: 621.396.1 Mor
A practical Treatise on Wireless Telegraphy and Telephony, giving Complete and Detailed Explanations of the Theory and Practice of Modern Radio Apparatus and its Present Day Applications, together with a chapter on the possibilities of its Future Development
Søgning i bogen
Den bedste måde at søge i bogen er ved at downloade PDF'en og søge i den.
Derved får du fremhævet ordene visuelt direkte på billedet af siden.
Digitaliseret bog
Bogens tekst er maskinlæst, så der kan være en del fejl og mangler.
WIRELESS TELEGRAPHY
II5
shaped piece of carbon. A second cup is mounted in a
rigid position directly in back of the first. The space be-
tween is filled with small polished granules of carbon.
Fig. 131.—Diagram of a telephone transmitter.
When these are in a perfectly free and loose state their
resistance to an electric current is very great, and they
allow almost none to flow.
When slightly compressed their resistance is greatly low-
ered, and they permit the current to pass. The vibrations
of the diaphragm exert a varying pressure upon the gran-
Fig. 132.—Diagram showing the principle and construction of the
telephone receiver.
ules, with a corresponding variation in their resistance and
the amount of current flowing.
The receiver, as has already been explained, consists of
a thin iron disk, placed very near but not quite touching
the end of a small bar of steel, permanently magnetized,
about which is wound a coil of fine insulated wire. The