Loading effects in resistance scaling

Reference resistors are affected by the heating of the resistor element caused by the measurement current. The effects of such loading are complex and can change in magnitude as a function or the initial state of the resistor and the external environment. This paper describes a method for determining relative lead coefficients by using cryogenic current comparator ratio measurements in a two-step scaling process, previously undiscovercd loading effects are analyzed using a resistance element made from copper, which has an easily measured change of resistance with temperature. The magnitude of loading effects in several types of resistors are listed.