| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a long-lived, small-sized and maintenance-free gas analyzer capable of effectively suppressing the deterioration of a filament to eliminate the change with the lapse of time of light emitting characteristic of an infrared light source by supplying a pulse current interrupted in a fixed period and having a duty ratio of repeat pulse varied in each period to the infrared light source. SOLUTION: Since this gas analyzer adapts a multiple modulation method for finely repeating ON/OFF, as a voltage for driving an infrared ray 13, and performing the ON/OFF in a period longer than the repeat period, occurrence of a notching phenomenon in a filament 16 constituting the infrared ray 13 can be suppressed. In each period, since the emitting interval is extended just after start, and the interval is thereafter narrowed, or the duty ratio of repeat pulse is set so as to gradually increase, the notching phenomenon or generation of rush current having a bad influence on the life of the filament 16 of the infrared light source can be suppressed.</p> |
