FYI, while I was searching for information on resistivity I came across this site. It covers various physics topics in a hypercard type format. I was unaware that copper wire's resistance decreased so much when very cold. Makes me wonder if superconducting materials are essential to make magnetic confinement schemes work.
http://hyperphysics.phy-astr.gsu.edu/hb ... html#ahph1
Dan Tibbets
Physics reference
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Re: Physics reference
Most conductors change resistance with temperature (constantan a notable exception).
Copper thermometers are very common in low temperature work. Copper is not a good candidate for use over 300 degrees celsius as it tends to oxidise rapidly( and if using a relay the insulation will limit you to what the insulation is rated to typically a max of 150 degrees celsius or less).
I have used relay coils for accurate temp sensors for years for ambient and below type temps.
you only need to know the resistance and temp at one point and it is linear over a large range.
much cheaper than Pt 100 sensors.
Copper thermometers are very common in low temperature work. Copper is not a good candidate for use over 300 degrees celsius as it tends to oxidise rapidly( and if using a relay the insulation will limit you to what the insulation is rated to typically a max of 150 degrees celsius or less).
I have used relay coils for accurate temp sensors for years for ambient and below type temps.
you only need to know the resistance and temp at one point and it is linear over a large range.
much cheaper than Pt 100 sensors.