A Multichannel Array-Driven Scanner With Low Thermal EMF

In this paper, a multichannel array-driven scanner with low thermal electromotive force (EMF) is proposed for precision electrical measurement. Three novel approaches are adopted to decrease the thermal EMF of the scanner and improve its stability. An array-type control and detection system is proposed to realize the closed-loop control of the relays, which can effectively simplify the control circuit and improve the control efficiency. The experimental results show that the thermal EMFs of all the channels are in the range from -11 to 17 nV with the Type A uncertainties varying from 1 to 2 nV. Further experiments indicate that the Allan deviation of the shorted channel of the scanner is less than 10
^-9
V in the sampling time from 10 s to 36 h.