| 摘要 |
PROBLEM TO BE SOLVED: To minimize a detection lower limit value without respect to a target element or varied measurement conditions. SOLUTION: Light emission from a tube 3 is monitored by means of an optical sensor 16, and in an operation quantity computing part 21, a firing angle as an operation quantity is computed on the basis of a difference between its signal value and a signal matching a target temperature according to a calculation algorism of PID control. In a pulse producing part 19, a pulse signal corresponding to the firing angle is formed for controlling turning on/off of a semiconductor switch 11 so as to control heating electric current flowing through the tube 3. A PID control constant can be inputted by a user via a keyboard 25, and when the PID control constant is corrected for properly changing an indicial response in a temperature rise, a valance between a dimension of absorbance and dispersion is adjusted and the detection lower limit value can be lowered.
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