A manual of practical medical electricity : the Röntgen rays and Finsen light . Fig. 51.—Current Reverser. to slide, and which are fixed at such a distance from eachother by a non-conductor as to allow of their making Accessories 97 contact with the central stud and either W. or N. Thearms are connected by the pivots on which they turn withthe two terminals of the battery-box. The central stud isconnected to the + pole of the cells, and W. and N. tothe — pole. In the position the arms are in in the diagram,the battery-box terminals are + and — respectively ; if (§;g<°)_. Fig
A manual of practical medical electricity : the Röntgen rays and Finsen light . Fig. 51.—Current Reverser. to slide, and which are fixed at such a distance from eachother by a non-conductor as to allow of their making Accessories 97 contact with the central stud and either W. or N. Thearms are connected by the pivots on which they turn withthe two terminals of the battery-box. The central stud isconnected to the + pole of the cells, and W. and N. tothe — pole. In the position the arms are in in the diagram,the battery-box terminals are + and — respectively ; if (§;g<°)_. Fig. 52.—Connections of Current Reverser. the arms are pushed over, the polarity of the terminals willbe reversed. Solid rheostats for interposing resistance there are solidand liquid forms. The solid are made of German silverwire (because it is but little affected by changes of tempera-ture), or of graphite. The plug rheostat or resistance box(Figs. 53 and 54) contains a number of coils of Germansilver wire ; each coil is wound with such an amount ofinsulated wire as to present a definite resistance, the twoends of the wire being connected severally to small brasspieces, which are securely fastened to an ebonite plates can be respectively connected with oneanother by the insertion between them of well-fitting brassplugs. When all the plugs are put in, the current flowseasily from brass piece to brass piece, from one end of thebox to the other ; but if a plug be withdrawn, the current iscompelled to travel round the coil of wire between the twobrass pieces, an
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectelectro, bookyear1902
