Electricity for public schools and colleges . s long as each end of the line is kept at zetvpotential (or the same potential), so long will the battery send a currentthrough it. (i) TJie electric bell.—The accompanying figure represents avery simple form of signalling instrument: it is similar in principleto the automatic make-and-break de-scribed in Chapter XXII. § 7. When in the position shown here{see fig. i.) the circuit is complete. Butas soon as a current passes, the electro-magnet attracts the iron keeper a,causing the hammer to strike the bell ,and the circuit is broken at the placewhe
Electricity for public schools and colleges . s long as each end of the line is kept at zetvpotential (or the same potential), so long will the battery send a currentthrough it. (i) TJie electric bell.—The accompanying figure represents avery simple form of signalling instrument: it is similar in principleto the automatic make-and-break de-scribed in Chapter XXII. § 7. When in the position shown here{see fig. i.) the circuit is complete. Butas soon as a current passes, the electro-magnet attracts the iron keeper a,causing the hammer to strike the bell ,and the circuit is broken at the placewhere the spring C touched the keepera. The current ceases, and with it themagnetism. Hence the keeper a is nolonger attracted ; and so, acted uponby the spring to which it is attached,it flies back again and makes contactonce more with C. The process isthen repeated. As long, therefore,as the current is kept on the line, solong will the hammer vibrate and thebell sound. This instrument is used only for attracting attention,not for tlL
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Keywords: ., bookcentury1800, bookdecade1890, bookpubl, booksubjectelectricity
