1-8
Proceed as follows:
1. Connect the Model 6517A to the DC current calibrator
using the low-noise coax cable, triax-to-BNC adapter,
and BNC-to-dual banana plug adapter, as shown in Fig-
ure 1-3. Be sure to connect the calibrator output HI ter-
minal to Model 6517A INPUT HI, and connect
calibrator output LO to Model 6517A INPUT LO.
2. Turn on the Model 6517A and the calibrator, and allow
a one-hour warm-up period before making
measurements.
3. Restore Model 6517A factory default conditions, as ex-
plained in paragraph 1.7.
4. Select the amps function and the 20µA range on the
Model 6517A.
5. With zero check enabled, press REL to zero correct the
instrument.
6. Set the calibrator output to 0.000µA then disable zero
check. Enable REL to null offsets.
7. Set the calibrator output to +19.0000µADC, and disable
Model 6517A zero check.
8. Allow the reading to settle, then verify that the Model
6517A reading is within the limits for the selected mea-
surement range, as summarized in Table 1-7.
9. Repeat steps 5 through 8 for the remaining ranges and
currents listed in Table 1-7.
10. Repeat the procedure for each of the ranges with nega-
tive currents of the same magnitude as those listed in
Table 1-7.
After calculating the actual voltage values, record them
where indicated in Table 1-6.
9. Set the DC calibrator to the actual voltage.
10. Make sure the DC voltage calibrator is in operate.
11. Allow the reading to settle completely, then note the
reading on the Model 6517A display. Verify that the
reading is within the limits listed in Table 1-6.
12. Reverse the calibrator voltage polarity, then make sure
the magnitude of current reading is within limits.
13. Repeat steps 4 through 12 for the 200pA through 2µA
ranges using the appropriate DC voltage and standard
resistor listed in Table 1-6. For each range, be sure to:
• Compute the actual calibrator voltage.
• Set the DC voltage calibrator to the correct setting.
• Null offsets using REL.
• Make connections to the appropriate standard resis-
tance in the calibration standard test box.
20µA – 20mA range verification
Measurement accuracy of the 20µA-20mA ranges is verified
by applying accurate currents from a DC current calibrator
and then verifying that the Model 6517A reading is within
specified limits.
Table 1-6
Reading limits for verification of 20pA-2µA ranges
6517A
range
Nominal
voltage
value
Standard
resistor
value
Actual
resistance
Applied
current
Actual
voltage*
Reading limits
(1 year, 18° to 28°C)
20pA
200pA
2nA
20nA
200nA
2µA
1.9000V
1.9000V
1.9000V
1.9000V
19.0000V
190.000V
100G
Ω
10G
Ω
1G
Ω
100M
Ω
100M
Ω
100M
Ω
__________
Ω
__________
Ω
__________
Ω
__________
Ω
__________
Ω
__________
Ω
19pA
190pA
1.9nA
19nA
190nA
1.9µA
_________ V
_________ V
_________ V
_________ V
_________ V
_________ V
18.8070 to 19.1930pA
188.095 to 191.905pA
1.89590 to 1.91410nA
18.9615 to 19.0385nA
189.615 to 190.385nA
1.89800 to 1.90200µA
* Voltage calculated as follows: V = IR, where V is calibrator voltage, R is actual value of resistance standard, and I is desired applied
current.