A precision setup and method for calibrating a DC voltage dividers ratios from 10 V to 1000 V

Resistive dividers are often used to calibrate DC voltage calibrators and voltmeters above 10 V, with ratio uncertainties lower than 10^-6. The dividers need therefore to be calibrated with uncertainties lower than 5*10^-7. A setup and method for the calibration of a resistive divider at its working voltage has been developed. The repeatability was found to be good enough to give standard deviations of the mean lower than +-1*10^-8 in the measured ratio 1000/10. The total uncertainties were estimated to be less than +-1.5*10^-7 (k=1) for all measured ratios.