The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 173
e bottom, and a very light aluminium shutter,p, pivoted at the top. The core of r is prolonged, and its end 148 PRACTICAL TELEPHONE HANDBOOK projects into a recess in a. The coil, o, of this combinationoccupies the place of the drop in an ordinary system. Itsarmature, A, is furnished with a long… … f^===3^r o,L^ -i r=^j N^ / ibt/A - q Fig. 162.—Full size disclose the number painted on a. Fig. 162 shows the dropin this position. The shutter is restored by the passage of a current ofsufficient strength through the coil r. This causes the at-traction of a, allowing p to fall into the vertical…
Telephone
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