A reference system to calibrate low-current meters in the range of picoamperes to microamperes

The calibration of low current meters in the range of picoamperes up to microamperes is important for the electronics industry, for the photometry area, and especially for the ionizing radiation area. In Brazil, traceability is limited to ten microamperes. In this paper, a reference system using Ohm’s law method is presented. It was possible to calibrate an electrometer between 2 picoamperes and 20 microamperes, with uncertainties between 0.70 % and 0.000060 %, respectively, as well as to validate the developed system and Ohm’s law method by comparing it with the method used to calibrate values above 10 microamperes, in an intralaboratory comparison.