The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 497
s, it is necessary to be able to measure currents, electro-motive forces, and internal resistances. Ammeters and Voltmeters.—Instruments for the directmeasurement of current strengths are called ammeters andthose for the direct measurement of P.D.s or E.M.F.s arecalled voltmeters. Both these… … Fig. 445.—Connections of Wheatstone Bridge for InductanceMeasurement usually provided with a thick wire coil of low resistance,which is inserted directly in the circuit to be tested, whilethe voltmeter has a coil of high resistance, which is connectedas a shunt to the circuit to be tested. Both…
Telephone
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