Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 71
utable to the samesource, which had since been found to bemore or less incorrect. The question of the efficiency of aprojector expressed, as in the curve inquestion, in the candle-power per wattascertained by diidding the maximumintensity of the rays incident on themirror by the energy consumption… … Fig. 4a.—Showing optical system of thesignalling projector above. The raysemanating to the right of the focal planeDB return on their own path to the sourceF and are then collected and refracted bythe lens. The rays included in angles AFB,EFD are reflected by the paraboloid surfaceinto a parallel…
Lighting
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