Journal of electricity, power, and gas . Fig. 2. When the well-known extensive, intensive andfocusing reflectors are used, it is a simple matter to. space the light-units correctly. It often happens, how-ever, that light-units giving other curves are to beused. For nearly every light-unit there is some min-imum value of k at which the best uniformity is ob-tained. Given the photometric curve, this value can,be obtained by the method described below. It shouldbe noted, however, that this method is applicable only January 10, 1914.] JOURNAL OF ELECTRICITY, POWER AND GAS 33 to curves having not m
Journal of electricity, power, and gas . Fig. 2. When the well-known extensive, intensive andfocusing reflectors are used, it is a simple matter to. space the light-units correctly. It often happens, how-ever, that light-units giving other curves are to beused. For nearly every light-unit there is some min-imum value of k at which the best uniformity is ob-tained. Given the photometric curve, this value can,be obtained by the method described below. It shouldbe noted, however, that this method is applicable only January 10, 1914.] JOURNAL OF ELECTRICITY, POWER AND GAS 33 to curves having not more than one general change incurvature in the lower hemisphere, such as the curvesshown in Figs. 1 and 2. What might be termed freakcurves, such as shown in Fig. 3, cannot be spaced togive uniform illumination efficiently. They are unde-sirable for general illumination. To determine the best k-value for curves as shownin Figs. 1 and 2, any slight irregularities should befirst eliminated and the dotted line curves shown in thefigures should be used. These dotted line curves arefor practical purposes the same as the solid line testcurves. Afte
Size: 1597px × 1564px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookcentury1800, bookdecade1890, booksubjectelectricity
