Keysight Technologies B1500A Self-Paced Training Manual page 109

Module 3
Low Current Measurement
This slide shows the open measurement results with ASU and without ASU.
The ASU provides the 1 pA measurement range and the stable measurement results as shown.
The 1 pA range is disabled with the default setting. To enable the 1 pA range, set the ranging mode
to LIMITED 1 pA (1 pA limited auto ranging) or FIXED 1 pA (1 pA fixed range).
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