I'm measuring temperature using a PT100 temperature sensor on a Wheatstone bridge. As I'm working on a battery powered application, I'm choosing the resistors in the bridge so that only a small current pass through it (to save power).

In my understanding, as long as I can measure the resistance of the RTD it should work, independent of the current flowing through it. Although, I know that the smaller the current, the smaller the signal I'll have to measure. However I'm puzzled by a section of the datasheet referring to a "measuring current". What does this parameter means? Is there a lower limit of the current flowing through the RTD for it to work properly?

This is the relevant section of the datasheet of the PT100 I'm working with: enter image description here

The full datasheet can be found here.



1 Answer 1


If you look at the headings of those columns, you will see that these are maximum values. The datasheet is saying that if you exceed those currents through the device, then enough heat will be generated that some accuracy claims will no longer be true, since the device is heating itself. There is no lower limit (although at some point the voltage difference generated will be so small that you will run into noise, either due to the limit of your ADC, or thermal noise (and probably other noise sources)).


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