Light, photometry and illumination : a thoroughly rev. ed. of ''Electrical illuminating engineering'' (1912)
Barrows, William Edward, 1878-1960 · New York ; London : McGraw-Hill Book Co. · leaf 278
he distribution of light from the unit chosen. At this point itAvould be well to refer to the polar curves near the end of ChapterIX and from the values of d/h given for ea^h polar curve onecan easily determine the height if the chosen unit has one ofthose types of distribution. Analyzing this… … Fig. 157.—Curves to give uniform illumination. (Two or more lamps.) other words, for uniform illumination, the maximum distancebetween lamps must not be more than 1/2, 3/4, etc., of theheight of suspension above the reference plane. Reflectors have been designed to meet the requirements ofthis…
Light · Photometry · Electric lighting
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