Is there any instrument for resistance measurement at reference temperature R0? 2

[npc-smart]

Hello everyone

Is there any instrument that is able to measure electrical resistance at reference temperature (25ºC) when the material is above 100 ºC.

The resistance of the material depends on the followings;
Rt = R0[(1+α(T-T0)]

Where:
R0: Is resistance from a material at reference temperature (25°C)
α: The temperature coefficient of resistance
T-T0: rise of temperature

I would like to measure with an instrument R0.

thanks in advance

 

[FacEngrPE]

Found with a web search.
HIOKI E.E. CORPORATION RESISTANCE METER RM3548
High-precision Portable Resistance Meter Measures from µΩ to MΩ, with temperature probe input.
I have never used one of these, your mileage will vary.

 

[IRstuff]

Sure, all you need to do is to figure out how to get α.

Your question is not making sense to me; measuring R0 is done at 25C, but you can do both with a curve of resistance vs. temperature

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[BrianPetersen]

If the temperature coefficient of resistance is unknown then you cannot infer the resistance at reference temperature if you only have one measurement at some other (presumably known) temperature. It fundamentally cannot be done. The single equation has two unknowns.

If you can make a measurement at two known temperatures then you can measure the resistance with any ordinary meter, and do the math to figure out both the coefficient and the resistance at reference temperature. Two equations, two unknowns, no problem, solve.

 

[npc-smart]

Thanks you all for answering me

I agree with @BrianPetersen and @IRstuff, I should be more specific. I have some silver wires (α known) threated at high temperatures. It takes some time to reach the reference temperature(25°C) once removed from an oven. Measuring the resistance at high temperature gives me a higher value than it would measure if it were in a reference temperature (25 °C), Furthermore, as the temperature decreases so does the resistance. So I want to simulate as if I were in a reference temperature (controlled room) with the condition that the wire has not yet cooled down completely.
So, I think there should be a measurement instrument that could help me.

I hope this clarifies

thanks in advance

 

[IRstuff]

Measuring the resistance at high temperature gives me a higher value than it would measure if it were in a reference temperature (25 °C), Furthermore, as the temperature decreases so does the resistance. So I want to simulate as if I were in a reference temperature (controlled room) with the condition that the wire has not yet cooled down completely.
So, I think there should be a measurement instrument that could help me.

You seem to be confused. Given a known α and the resistance at temperature, you use the equation you cited to calculate what the reference resistance is. There is no other way to do this without changing the temperature; you can change the temperature by, say, 20 degC, and use the two measurements to confirm α and R0, but it's not as reliable as going directly to 25 degC. Treatment of the material potentially changes α, so doing a two-point measurement will at least guarantee some level of verisimilitude. There is no way to infer R0 without valid α and a single temperature measurement, and the only consistent approach to confirm both is to use two temperatures.


TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[Gr8blu]

The other way to write the equation is as follows.
(Rhot) = (Rcold) * (234.5 + Thot) / (234.5 + Tcold)
Where R = resistance in ohms, T = temperature in degrees Celsius

With what I do, Tcold is almost always the "reference" temperature because I'm typically interested in how high the resistance will get when the temperature increases during operation.

Converting energy to motion for more than half a century