Thermocouple Research Op!

In my profile I state that I’m a college student in serious need of a good part time job. Well guess what everyone, I’ve finally got one! I’m working as a research assistant for Dr. Donaldson at NMSU. I’m to help design and conduct experiments to better understand the effects of thermocouple drift.

I stole this from here, and thought I’d post it up as it seems worded perfectly.

All thermocouples are subject to calibration drift with use, it is just a matter of how much, and how fast this may happen. Thermocouple performance is critically dependent upon absolute uniformity of both physical and chemical properties along the entire length of the wires in the circuit. This is because the thermoelectric emf produced by the thermocouple is a combination of the emf produced at every point along its length.

In sort inhomogeneities or imperfections tend to occur over extended use and are more common if the wire is exposed to extreme environments. The more extreme the environment (whether it be extremities of temperature, radioactive or chemical) the more likely the metallic properties of the wire will degrade (or “drift”) and thus alter the accuracy of the reading.