User`s guide

7-30 Agilent 4155C/4156C User’s Guide Vol.2, Edition 6
Measurement Units and Functions
Measurement Ranging Mode
Auto Ranging
The monitor unit automatically searches for and measures at the range that provides
the highest resolution as follows:
V measurement
The unit changes ranges (up or down one range at a time) until the measurement
value is between 10 % and 110 % of the range, then the unit performs the
measurement.
I measurement
•1 A to 1 μA
The unit changes ranges (up or down one range at a time) until the measurement
value is between 10 % and 114 % of the range, then the unit performs the
measurement.
If the measurement value is less than 1 % of the present range and the present
range is 100 μA or higher range, the range changes down two ranges instead of
one range.
• 100 nA to 100 pA
The unit changes ranges (up or down one range at a time) until the measurement
value is between 10 % and 114 % of the range, then the unit performs the
measurement.
• 10 pA
The unit changes to the next higher range when the measurement value exceeds
104 % of the present range.
The auto ranging operation can be expanded for the current measurement. See
“Enhanced Auto Ranging for Current Measurement” on page 7-33.