Performance Verification 18-25
1pA-100nA range accuracy
1. With the power off, connect the digital multimeter and calibration standard to the main-
frame and PreAmp as shown in Figure 18-7. (Connect the mainframe INPUT/OUTPUT
HI and LO jacks to DMM INPUT HI and LO respectively. Connect the PreAmp IN/
OUT HIGH jack directly to the Model 5156 OUTPUT jack, and connect the BNC
shorting cap to the 100GΩ resistance jack. Also be sure to remove the link between
the Model 5156 SHIELD and CHASSIS jacks.)
2. Select the multimeter DC current function.
3. Set the Model 6430 to both source and measure current by pressing the SOURCE I and
MEAS I keys, and make sure the source output is turned on.
4. Verify measure current accuracy for the currents listed in Table 18-13. For each
measurement:
• Connect the BNC shorting cap to the correct Model 5156 resistance jack.
• Select the correct source range.
• Calculate the current from the DMM reading and actual standard resistance:
I = V/R.
• Set the Model 6430 source output to the calculated current.
• Verify that the Model 6430 current reading is within the limits given in the table.
NOTE It may not be possible to set the current source to the specified value. Use the closest
possible setting, and modify reading limits accordingly.
5. Repeat the procedure for negative currents with the same magnitudes as those listed in
Table 18-13.
Table 18-13
Remote PreAmp 1pA-100nA range measurement accuracy limits
Model 6430
range
Standard
resistor
1
Source current
Model 6430 current reading
limits (1 year, 18°-28°C)
2
1pA
10pA
100pA
1nA
10nA
100nA
100GΩ
100GΩ
10GΩ
1GΩ
1GΩ
100MΩ
1.000000pA
10.00000pA
100.000pA
1.00000nA
10.0000nA
100.000nA
0.98300 to 1.01700pA
9.9430 to 10.0570pA
99.820 to 100.180pA
0.99930 to 1.00070nA
9.9930 to 10.0070nA
99.930 to 100.070nA
1
Nominal values. Use characterized values in current calculations.
2
Calculated from DMM reading and nominal resistance values. Use closest value, and modify reading limits
accordingly. Limits shown include Model 5156 characterization uncertainty.
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