An elementary book on electricity and magnetism and their applications . ct with electric light wires, yet a great deal of inconvenience iscaused by their unsatisfactory and leaky character. This is the con-dition of numberless electric-bell circuits in houses all over the countrywhere the front door bell fails to ring when the button is pushed. Thetrouble is caused by the batterys being run down through the con-stant flow of current leaking from poorly insulated wires where theycome in contact with dampness or at some point where they are bothplaced under one metal staple. The difficulty, in
An elementary book on electricity and magnetism and their applications . ct with electric light wires, yet a great deal of inconvenience iscaused by their unsatisfactory and leaky character. This is the con-dition of numberless electric-bell circuits in houses all over the countrywhere the front door bell fails to ring when the button is pushed. Thetrouble is caused by the batterys being run down through the con-stant flow of current leaking from poorly insulated wires where theycome in contact with dampness or at some point where they are bothplaced under one metal staple. The difficulty, in a great majorityof the cases, would never have appeared had wire with good rubberinsulation been used. As No. 18 wire of the Brown and Sharpe gaugeis usually taken for bell circuits, the extra expense caused by usinu:rubber-covered or weatherproof wire is not very great, while theinconvenience avoided by its use may be considerable. It must not be assumed, however, that all the troubles to whichbell circuits and similar circuits are subject arise from poor ELECTRO MAGNETISM 99 Battery zincs become used up or the water evaporates, and the batterymay not work on that account. The mechanism of bells and pushbuttons is very simple and not likely to get out of order, but troublemay occur even in them. The contact parts in a push button gradu-ally become corroded, and then when the button is pushed it does notcomplete the circuit. This fault is easily remedied by taking thecover off the button and scraping the contact points. If a leak occurs from wire to wire, the battery remains in actionall the time, the depolarizer (if the battery has one) soon becomes
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmagnetism, bookyear19
