Illuminating Engineering Volume 5

Illuminating Engineering Volume 5

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 edition. Excerpt: ...of the candle-power involved in a false adjustment of the lamp whereby it is not placed with its filaments exactly at right angles to the bar is very small, and the consequences of a mistake of this kind are minimized. Ordinarily in the interests of long life, carbon filament lamps are standardized operating at about 4 watts per candle. This involves the disadvantage that the light of the lamp is somewhat redder in hue than that of most of the lamps which are to le compared with it, though this disadvantage is not a very serious one until metal filament lamps are reached. The comparison of a tungsten lamp at 1.25 watts per candle with a carbon lamp at 4 watts per candle involves very great uncertainties on account of color difference. On this account the Laboratories have as a result of many measurements by many observers and by intercomparison with other laboratories,1 established a set of tungsten standards, the candle-power of which is known in terms of the carbon standards. The color difference difficulty having been met once for all, is eliminated in future work with tungsten lamps by the use of tungsten standards. A great deal of attention has been given recently to the question of standardizing tungsten lamps, since this type of lamp beingvery little subject to change in candle-power, would seem to make an ideal standard, not only for the measurement of tungsten lamps, but also for carbon lamps as well. In the latter case the tungsten standards would be standardized at a sufficiently reduced voltage to bring their color to the right quality. It has been found that the ordinary commercial type of tungsten lamp does not admit of very accurate standardization. The difficulty seems to be that 1 The Problem of Heterochromatic...show more

Product details

  • Paperback
  • 189 x 246 x 13mm | 431g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236951999
  • 9781236951991