The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 77
beregulated by the screw v. The terminals of the instrumentare connected one to b b and the other to the metal case, thelamp-black thus forming part of the circuit. Speaking on the diaphragm causes it to vary its pressureon the carbon, producing corresponding variations in theresistance of a… … Fig. 38 HISTORY 55 much louder with this instrument than when a magnetotransmitter is used. Induction Coil.—Edison still further augmented the powerof the instrument, especially when used over long distances,by using an induction coil in conjunction with his trans-mitter. The carbon and battery…
Telephone
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