Telegraph engineering : a manual for practicing telegraph engineers and engineering students (1922)
Hausmann, Erich, 1886- · New York : D. Van Nostrand Company · leaf 71
WG Fig. 10. mitters, represented by C and C\ consist of double arma-ture relays, each armature playing between two contactstuds. When the key K is not depressed, retractile springshold the armatures x and y respectively in contact withthe positive and negative terminals of the battery B, butwhen…
Telegraph
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