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—A high accuracy current source has been developed for the generation of very small currents (below 200 pA) based on applying a linear voltage ramp to a capacitor. Using software-controlled compensation for the nonlinearity of the voltage ramp, a stable current can be reached within a few seconds. A voltage ramp within typically 10 10 6 of any desired value(More)
The dc properties of a set of recently developed ac-dc transfer current shunts in the range of 30 mA to 10 A are presented. The characterization includes the long-term drift, temperature coefficient (TCR) and power coefficient (PCR), which all appear to have effects on the level of 1 – 10 μΩ/Ω. After corrections for the TCR and PCR, the uncertainty in the(More)
—A new methodology for conductivity measurements, where square metallic samples are measured with the Van der Pauw technique, has been successfully implemented. The uncertainty obtained is 0.04% and a comparison between national metrology institutes gives an agreement of the measurement values within 0.035%. Major advantages of the new method are that(More)