Resistance Programming Accuracy
For N6781A and N6785A
Test category = performance, calibration
Current readback accuracy must be verified prior to this test.
Step 1. Turn off the power system and connect an external DMM and an electronic load directly to the
output (see Test Setup F).
Step 2. Turn on the power system and set the 20 V range, and program the output to 10 V. Turn the
output on and record the voltage reading on the DMM. This is the voltage with no load (Vnl).
Step 3. Program the output resistance to 1 ohm. Turn on the electronic load. Select CC mode, current:
1 A, Input On.
Step 4. Record the voltage reading on the DMM. This is the voltage with a load (Vwl). Record the
current reading on the front panel of the power system. This is the current with a load (Iwl).
Step 5. Calculate the resistance value as follows: R = (Vnl−Vwl)/Iwl This is the output resistance,
which should not exceed value listed in the test record under “Resistance Programming”.
Step 6. For Model N6781A, repeat steps 2 through 5 for the 6 V range. Set the output voltage to 6 V
and the load current to 3 A.
Negative Current Output - Models N6783A-BAT and N6783A-MFG
Test category = performance, calibration
Step 1. Turn off the power system and connect the DMM, current shunt, and an external power supply
to the output (see Test Setup H). Connect plus to plus, minus to minus. Set the external power supply
to 3V, 3A.
Step 2. Turn on the power system and set the N6783A power module to the values indicted in the test
record under “Negative Current Output”. The display should read approximately -2 A.
Step 3. Divide the voltage drop (DMM reading) across the current shunt by its resistance to convert to
amperes and record this value. The reading should be within the limits specified on the test record
under Constant Current Tests, “Negative Current Output”.
6 Verification and Calibration
342 Keysight N6700C Operating and Service Guide
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