Fluke 9100 - Page 239

Section 4: Using the Model 9100: Capacitance Function 4.13-11
Final Width = 215mm
4.13.5.7 Spans of Source Currents
In the synthesized capacitance technology used in the 9100, the constant current sourced from the UUT must fall within a maximum
of two spans of values (Spans 1 and 3 as shown below) for each dialled capacitance value. The spans of constant source currents
acceptable to the 9100 are shown against their corresponding spans of output capacitance in the following table:
♦ = No corresponding span available
Hardware Configuration Limits Constant Source Current Limits
on Span of Output Capacitance UUTi Low UUTi High UUTi Super
0.50000 nF to 4.00000 nF 0.02µA to 500µA ♦♦
4.00001 nF to 40.0000 nF 0.02µA to 500µA ♦♦
40.0001 nF to 400.000 nF 0.04µA to 1mA ♦♦
0.40001 µF to 4.00000 µF 0.5µA to 1mA ♦♦
04.0001 µF to 40.0000 µF5µA to 3mA ♦♦
040.001 µF to 400.000 µF5µA to 3mA ♦ 2.5mA to 35mA
0.40001 mF to 4.00000 mF 5µA to 3mA ♦ 2.5mA to 35mA
04.0001 mF to 40.0000 mF 5µA to 3mA ♦ 2.5mA to 35mA
When the Capacitance function is entered from another function, the default capacitance setting is 10µF (in the 0.4µF-40µF
capacitance span), coupled with its only available current span: 'UUTi Low' (5µA to 3mA). 'UUTi Low' will persist for all changes
between capacitance spans, but in the three upper spans (40µF-40mF) 'UUTi Super' can be selected by pressing the CHANGE
CURRENT
screen key (refer to pages 4.13-2/3). Once selected, UUTi Super will persist until one of the lower five spans (0.5µF
to 40µF) is selected, when the 9100 reverts to UUTi Low. The indications given on the screen for the two different spans are as
follows:
UUTi Low UUTi High UUTi Super
U
U
T
i
Not Used
U
U
T
i
Output Voltage Limitation
At any UUTi span, the 9100 will seek a suitable configuration of hardware to accommodate both the value of source current within
the limits, and the value of capacitance set as Output Value. The maximum output voltage for guaranteed proper operation is 3.5V
(2.5V on 4µF to 40µF span). Under some conditions, a higher voltage can be obtained.
Any Capacitance value within the total span can be selected. However, if the source current exceeds the upper limit of the selected
span, the circuit will be saturated, and a warning will be given. When a warning appears, the instrument will still function, but the
specification will be compromised.
Always use UUTi Low unless the 'Sense current high' warning appears, then choose UUTi Super, if available. Always try to use
the smallest possible current.