Question

como llego de la fomula R2/R1 = T+t2 / T+t1 ------> R2 = R1 [ 1+ alfa (t2-t1)]
son formulas de la temperatura en un conductor

Answer 1

Respuesta:

Explicación:

'm trying to do a simple calculation to find the electrical resistance of a copper coil at a different temperature. I thought I knew the equation but to check I took my results an worked it backwards and got a different result than I started with. I did a web search and found several online calculators and which give the exact same result.

Here's what I've got:

copper coef. of resistivity alpha = 0.00393 /deg C

T1 -40 deg C

R1 5 ohms

T2 20 deg C

R2 = R1[1+alpha(T2-T1)] = 6.179 ohms

But when you back solve it

T1 20 deg C

R1 6.179 ohms

T2 -40 deg C

R2 comes out 4.715 ohms, not the 5 ohms I started with.

I can see what is going on here, in the first case the [1+alpha(T2-T1)]