A low thermal EMF relay-based scanner for precision resistor load coefficient calibration system

A low thermal electromotive force (EMF) relay-based scanner is proposed to improve the calibration efficiency of the precision resistor load coefficient calibration system in this paper. Three approaches are put forwarded to help decrease the typical thermal EMF of the scanner until below 20 nanovolt (nV). Experimental results indicate that the calibration error introduced by the scanner is at 10
^-8
level when the scanner is used in the load coefficient calibration system for 100 Ω resistors.