Elementary telegraphy : a manual for students; written specially to meet the requirements of the ordinary grade of the subject as published in the syllabus of the city and guilds of London Institute (1910)
Pendry, H. W. (Henry Walter) · London ; New York : Whittaker & Co. · leaf 66
d with large currents. Suchoxidation introduces resistance at the points of contact,sometimes causing even a disconnection. The back contactscrew carried by the lever is adjustable. The electricalconnections of the two stops and the bridge are shownin Fig. 27. Xormally the lever is held in contact… … Fio. 27.—Electrical connections of S.C. key. form of horseshoe electromagnet with the two coils con-nected in series and the ends of the wire joined to tM^o
Telegraph
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