A resistor having low temperature coefficient of resistance includes a resistive part and two conductive parts connected to opposite sides of the resistive part. One conductive part has a through slot and a sensing portion between the through slot and the resistive part. The through slot has two inter-connected sections. Each section extends and ends with a closed end and has a parallel component, parallel to a main current direction defined on the resistor, and a perpendicular component, perpendicular to the main current direction. Another resistor having low temperature coefficient of resistance includes a resistive part and two conductive parts connected to two sides of the resistive part respectively. Each conductive part has a protrusion block, extending outward perpendicular to a main current direction defined on the resistor, and a sensing portion at the protrusion block.