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 33
tation will be rung by central. Each extension has its own ringing key forringing from the main which makes the system intercommunicating. Each station isfed by its own battery and each has its own magneto. This is called plan 5 magneto bythe New York Telephone Co. 2,126 HAWKINS ELECTRICITY Ques.… … I7ig. 2,930.—The Blake microphone transmitter. In this instrument a single contact is main-tained between the platinum point A and the polished carbon button B, by means of theadjusting screw C, acting against the strip of iron D, called the anvil. The vibrations ofthe diaphragm thus affecting the…
Electrical engineering
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![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten07unit-617-390.webp)
