I'm looking to get a very high precision temperature measurement over a somewhat small range. Ideally, I want at least a 0.001 Celsius increment, over a -5C to 5C range. Searching Digikey doesn't seem to leave me with anything that could accomplish this. Is there a sensor that I could use to accomplish this?
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\$\begingroup\$ Out of curiosity, what project is this for? \$\endgroup\$– DanielOct 15, 2015 at 1:16
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\$\begingroup\$ I would say an in amp across a tiny rectifier might work. Self-heating could be an issue though. \$\endgroup\$– Ignacio Vazquez-AbramsOct 15, 2015 at 1:24
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2\$\begingroup\$ This is for measuring the surface temperature of lakes at high altitudes (in/around mountain ranges). \$\endgroup\$– froggyOct 15, 2015 at 1:34
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I would use a platinum RTD for this purpose. Some precision thermistors might also be suitable.
If you calibrate the sensors and signal chain individually at the triple point of water (single point calibration) then the accuracy of the sensor should be fairly good over such a narrow range.
The optimal current will depend on whether the sensor is in contact with the water and on sensor construction (self heating variation) but at say 0.2mA a 100 ohm RTD will give you a fairly healthy 77 uV per millikelvin, so a good performance signal chain should not be limiting.
answered Oct 15, 2015 at 4:09
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\$\begingroup\$ This sounds almost exactly what I'll be going with. I contacted Atlas-Scientific (atlas-scientific.com) to see what they had to say about this, and was informed they'll be releasing a new product soon that will do exactly what I described. From what I gathered, it will be using a platinum sensor probe, and likely have a supporting high performance instrument amplifier accompanying it. \$\endgroup\$– froggyOct 16, 2015 at 1:29