The resistance-temperature coefficient (α) is defined as the rate of change of the zero-power resistance associated with a temperature variation of 1℃ at any given temperature.
The relationship between the resistance-temperature coefficient (α) and the B value can be obtained by differentiating equation 1 above.

\[ a = \frac{1}{R} \cdot \frac{dR}{dT} \times 100 = - \frac{B}{T^2} \times 100 \begin{pmatrix} ％/℃ \end{pmatrix} \]

A negative value signifies that the rated zero-power resistance decreases