A PRECISION DC LOW-CURRENT SOURCE FOR CALIBRATION OF ELECTROMETERS IN THE RANGE OF 100 pA TO 1 fA

Wan-Seop Kim, Mun-Seog Kim, Dan bee Kim, Young Gyun Kim, Po Gyu Park

Abstract

A precision DC low-current source based on charging a capacitor with a linearly varying voltage ramp was built to calibrate low-current meters in the range of 100 pA to 1 fA. For a calibration of Keithley 6430, the relative expanded measurement uncertainty (<i>k</i> = 2) was evaluated to be 16 µA/A ~ 62 mA/A within the current range. In the calibration process, it was observed that the offset current of the capacitors lead to a crucial contribution to the measurement uncertainty.

Keywords

DC low-current, voltage ramp, capacitor, picoammeter

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IMEKO-WC-2012-TC4-P20.pdf

DOI

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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