A precision 10 mA current shunt is used to calibrate AC current at 1 mA and 100 /spl mu/A levels

The calibration of low AC current at 1 mA and 100 /spl mu/A is described using current divider techniques. Uncertainties are calculated for 9:1 and 99:1 current division ratios. A builddown method is used stepping from 10 mA to 1 mA and from 1 mA to 100 /spl mu/A using a NIST-calibrated 10 mA current shunt as the reference.