American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 257
WESTERN UNION NEUTRAL RELAY. within its covers, are contained several separate series of resistance coils; rr and c^represent the retarding coils placed before the static compensating condensers c^ c^; … r is the resistance coil equalling the resistance of the main line; gc is the ground coil,thrown into circuit when the switch sp is turned to the right in the figure; its resistanceis made to equal the internal resistance of the full battery mb. THE QUADRUPLEX. 215 FIG. 173.
Telegraph
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