Electricians' operating and testing manual; (1910)
Horstmann, Henry C. [from old catalog], Tousley, Victor Hugo, 1875- [from old catalog] joint author · Chicago, F. H. Drake & co · leaf 298
lamps is often measured bymeans of the dispersion photometer first suggested byProf. Ayrton. The principle of the arrangement isshown in Figure 180. The light from the arc is al-lowed to pass through a dispersion lens which spreadsit out over a greater area and thus lessens its intens-ity. Since… … Figure 180 illuminated by the dispersed light. The lens limitsthe quantity of light, and as it is circular we maytake the diameter of the circle illuminated as thesquare root of the area. The intensity of the light isthen the same as though the distance from the arc tothe screen were equal to D…
Electrical engineering · Electric testing
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