A dictionary of electrical words, terms and phrases (1898)
Houston, Edwin J. (Edwin James), 1847-1914 · New York, The W. J. Johnston company · leaf 33
mmunicatewith the central office, blows through thespeaking tube in his room, and thus, byeffecting an electric contact, rings a bell andoperates a drop at the annunciator, thus indicat-ing the exact tube at which the attendant is toreceive the message. The attendant can thus beplaced in easy… … Fig. 17. Needle-Annunciator. which, when at rest, points vertically down-ward, and which is moved to the right or leftby the action of the current. Pendulous, or swinging-annunciators are gen-erally so arranged as to need no replacement. Auo.] U [App. On the cessation of the current the indicator…
Electricity · Electrical engineering
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