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 83
Fiij. 4il.—N(,n-poIarized relay D. A small iioii-]i()larizod relay called I) (illustrated inFig. 40) has live terminals lor simplex W(U-king. Iiesist-ance of coils 200. it will res])ond to current of2 m.a. andcan be biassed ai-ainst 15 m.a. 72 ELEMENTARY TELEGRAPHY Kkvs. A ff)rni of key designed… … Fk:. 47. —S.C. key with switch. internal connections are Aaried by the moAcment of tlieswitch, as can be traced in Fig. 48. With the switch to send the action of the key places first one battery andthen the other in connection with the line, Avhile Avith theswitch to receive the batteries are…
Telegraph
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