| 摘要 |
PURPOSE:To facilitate mechanical adjustment and improve accuracy of measurement, by gain-controlling the photoelectric current value obtained by the measurement through a variable resistance. CONSTITUTION:Light from a light source 1 becomes parallel light by a lens 2, passes through a filter 3, a measuring cell 4 and is incident on a photocell 5. Output photoelectric current passes through a current-voltage converter 9, which is connected to one of the resistances of a variable resistance group R1-R4, the converted to a digital signal by an A-D convertor and is inputted to a computer 13. In the computer 13, the input voltage is determined whether it is within the optimum input voltage range or not, and if not, switches S1-S5 are successively changed over and an optimum resistance is selected. This arrangement facilitated mechanical control, and improves measurement accuracy. |
