This table shows a brief comparison of the types of commonly used temperature sensors. An RTD (resistance temperature detector) may use platinum, nickel or copper for its element while a PRT (platinum resistance thermometer) is a type of RTD that uses platinum for its element.  I.C.s can have extra features built–in, like alarms, or integrated DACs and ADCs. Finally, thermocouples measure relative temperature, not absolute temperature. Therefore, the accuracy of thermocouple temperature measurement is limited by the accuracy of the cold junction compensation.