Platinum IR sources for NDIR gas monitors

The work presents the results of research of the new thermal IR sources to be used in NDIR (nondispersive infrared) gas monitors. The developed sources are adapted to direct modulation that consists of supplying the heater with variable voltage. Appropriate heat transfer makes it possible to reach a modulation frequency as high as 50 Hz. This value is considerably greater then the frequency limit that can be obtained for other IR sources. The sources show very good dynamic parameters, which makes them suitable for fast measurements of concentration.