Betekenis van:
photoelectric cell

Voorbeeldzinnen

1. In some types of opacimeter the gas between the light source and the photoelectric cell, or between transparent parts protecting the source and the photoelectric cell, is not of constant opacity.
2. The construction of the electrical circuit, including the indicating dial, shall be such that the current output from the photoelectric cell is a linear function of the intensity of the light received over the operating-temperature range of the photoelectric cell.
3. The impingement on the photoelectric cell of stray light due to internal reflections or diffusion effects shall be reduced to a minimum (e.g. by finishing internal surfaces in matt black and by a suitable general layout).
4. In determining the effective length of the light path through the gas, account shall be taken of the possible influence of devices protecting the light source and the photoelectric cell.
5. The check consists in verifying that this value does not differ by more than 0,05 m-1 from that read on the opacimeter indicating dial when the screen is introduced between the source of light and the photoelectric cell.
6. The response time of the electrical measuring circuit, being the time necessary for the indicating dial to reach 90 % of full-scale deflection on insertion of a screen fully obscuring the photoelectric cell, shall be 0,9 to 1,1 seconds.
7. The electrical circuit of the photoelectric cell and of the indicating dial shall be adjustable so that the pointer can be reset at zero when the light flux passes through the smoke chamber filled with clean air or through a chamber having identical characteristics.
8. The receiver shall consist of a photoelectric cell with a spectral response curve similar to the photopic curve of the human eye (maximum response in the range 550/570 nm; less than 4 % of that maximum response below 430 mm and above 680 nm).