Answer to Question #113758 in Electric Circuits for Mike

Question

The temperature coefficient of resistance for carbon at 0oC is -0.0048/oC. What is the significance of the minus sign? A carbon resistor has a resistance of 500Ω.Determine its resistance at 50oC

Answer 1

Minus sign shows that on increasing the temperature the resistance value will decrease or vice versa

$R=R_o(1+\alpha(T-T_o)$

$R=500(1+(-0.0048(50-0))=500(1-0.0048\times50)=500\times0.76=380 ohm$