Hawkins electrical guide ... : questions, answers & illustrations : a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications ; a practical treatise (1914)
Hawkins, N. (Nehemiah), 1833-1928 · New York : T. Audel & Co. · leaf 34
TRANSMITTER Figs. 2,931 and 2,932.—Combined tele-phone set and switchboard for smallsystem. A switcnooard, whether com-bined with a magneto instrument asshown, or a separate piece of appa-ratus, is a device by means of whichtwo or more telephone lines may beconnected. In its simplest form,…
Electrical engineering
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![An illustration from Telephones and telegraphs: 1902 : [and Municipal electric fire alarm and police patrol systems] (1906)](https://img.insideoutlibrary.com/img/200/ia-cu31924022817674-64-23.webp)
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer03inte-77-24.webp)