Temperature coefficient of resistance

logearav

Joined Aug 19, 2011
243
The formula for temperature coefficient of resistance is
$$\alpha$$ = ΔR/R0 ΔT
where R is R - R0, where R0 is the resistance at reference temperature usually at 0°C or 20°C.
ΔT is T - T0, again T is 0° or 20°C
when written explicitly we get
$$\alpha$$ = (R - R0)/R0 (T - T0)
But while measuring temperature coefficient of resistance of the material of the coil, in metre bridge experiment,
we use the relation $$\alpha$$ = R2 - R1/(R1t2 -R2t1).
How R1 and R2 comes in this relation, whereas in the original formula there is only R0.

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Kermit2

Joined Feb 5, 2010
4,162
There is no difference other than the choice of variable names.

MrChips

Joined Oct 2, 2009
21,869
It appears that you are using equations from two different sources.
Just substitute R = R2, R0 = R1. Also T = t2, T0 = t1.