Sentence Examples


  • The Korn telephotographic apparatus is based on the principle of an apparatus devised by Shelford Bidwell in 1881 for the electrical transmission of pictures to a distance, in which use was made of the change in electrical resistance which selenium undergoes when acted upon by light.
  • A totally reflecting prism placed inside the glass cylinder projects the light which penetrates the film upon a selenium cell situated at the end of the cylinder.
  • An illumination of variable intensity (according to the deeper or lighter shades of the portion of the picture on which the light falls) thus takes place on the selenium cell.
  • As the glass cylinder, driven by a motor, revolves upon its axis while also advancing (by means of a screw thread on the axis), all portions of the picture are successively brought under the beam or pencil of light and cause a beam of varying intensity to fall on the selenium cell.
  • Owing to the variable illumination of the selenium thus produced, the resistance of the latter, and therefore the intensity of the current sent through the line to the receiving station by the battery, will be altered accordingly.

How would you define selenium? Add your definition here.

comments powered by Disqus