Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 581
such an extent that no noise whatever will be heardin the talking circuits deriving currents from the terminals of thebattery during the use of the machines. Obviously, if the voltageacross the terminals of the storage battery were subject to rapid peri-odical fluctuations due to the action of the… … FIC. 400.—IMPEDANCE COIL. chines, to place a heavy impedance coil in tlie charging leads to re-duce the fluctuations in current and consequent noise in the talkingcircuits, and even with this it was often necessary to charge only insuch hours as the exchange was least busy, that is, at night.…
Telephone
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