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Converting resistance to temperature

I have got a 120 ohm nickel resistance temperature detector(RTD) and am interested in a formula that converts the decreasing ohmic value across this type of device to a corresponding increase in temperature.

James Whitley
- Sherwood, Arkansas
2002

Pure nickel has a POSITIVE temperature coefficient of resistance of 0.0047 per degree C. Now that you know the approx. value, try measuring it in well-stirred ice-water and in boiling water. Watch out for the math though, it's based on 0.0047 of the present reading. So if at some temperature it measures, say, 124 ohms, when it is 1 degree hotter it will be 124*(1+0.0047) or 124.5828 ohms.

Tom Gallant
- Torrance, California, USA
2002