The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 500
— = 455 ohm. The defect of the above methods is that the E.M.F. mayvary during the two tests, the current being stronger in thefirst case, and the polarisation consequently greater. Current Strength,—In the absence of an ammeter, the ELECTRICAL MEASUREMENTS 471 strength of the current passing… … Fig. 447.—Connections of Voltmeter Ohms law(c = -J the strength of the current is given in amperes. As currents of much less than 1 ampere in strengthare generally used in telephony, it is more usual to measure inmittianiperes, which is a unit = T^oth of an ampere. The formula then becomes c = . It…
Telephone
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