Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 28
saryto make a recalibration. In the measurement of candle-powerthe following device is used. The testplate on the end of the elbow tube isitself attached to a short tube whichslips into the elbow. At the inner endof this short tube is a diaphragm. Thetube may be pulled out and reversed,bringing the… … Fig. i.—Illustrating use of photometer withdetached test plate. is set up at a distance of one foot fromthis test plate, its candle-power isread directly from the scale, no recali-bration of the instrument being re-quired. In a great majority of cases it isfound more convenient to use a…
Lighting
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