The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 189
indrical metal cover, which is notshown, is passed over, and screwed on, rendering the wholedust-proof. This is called a single make relay, and is usually 164 PRACTICAL TELEPHONE HANDBOOK wound with 11 mils wire to a resistance of 60 ohms. It workswith a current of 20 milliamperes. Kellogg Pattern… … b keeps the armature in position. When attracted, the latterrocks on the knife edge, and insulated studs on the upperend raise the long centre springs at d from the lower springsinto contact with the upper short springs shown. In Fig. 187 the instrument is shown furnished with a tripleset of three…
Telephone
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