A dictionary of electrical words, terms and phrases (1898)
Houston, Edwin J. (Edwin James), 1847-1914 · New York, The W. J. Johnston company · leaf 22
f central-station fire-alarms are constructed on a similarplan. Alarm, Electric An automatic de-vice by which attention is called to the occur-rence of certain events, such as the openingof a door or window; the stepping of a personon a mat or staircase; the rise or fall of tem-perature beyond a… … Fig. 7. Electrically Started Mechanical Alarm. which is electrically called into action by eitherclosing or opening an electric circuit, generallythe former. Electric-alarms may be divided into two classes,viz.: (1.) Mechanically operated alarms, or those in which the alarm is given by clock-work,…
Electricity · Electrical engineering
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