The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 302
Fig. 280 loops, with condensers, as shown in Fig. 280. These relays hav-ing heavy slowly-moving armatures are operated by ordinaryalternating currents sent through the loop, and while so ener-gised, and the bells therebyconnected through the 4>contacts, the appropriate \J)unidirectional…
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
