Fluke 5720A service manual Optional Tests, DC Voltage Load Regulation Test

5700A/5720A Series II Calibrator

Service Manual

21.Push the CLEAR REF WBND soft key on the 5790A. The 5790A wideband output changes to 10 mV at 1 kHz.

22.Push the SET REF soft key on the 5790A when the 5790A settles to a reading. This is the 10 mV reference value from which all other frequencies will be compared.

23.Repeat steps 7 and 8 above for each frequency through 30 MHz. Only the 10 MHz, 20 MHz and 30 MHz points are adjusted.

24.Make sure the rear panel CALIBRATION switch is in the ENABLE position. Store the cal constants by pushing the STORE VALUES softkey. When the display returns to normal, set the rear panel CALIBRATION switch to NORMAL. The Calibrator wideband flatness calibration is now complete.

3-31. Optional Tests

These tests may be used in acceptance testing or following repair likely to affect the characteristics tested here. They are not recommended to be done routinely. If the Calibrator passes Calibration Performance Verification, you do not need to perform these tests; verification either exercises these functions or is subject to their effects. The Optional Tests include such checks as load regulation, noise, and distortion. Equipment required for the optional tests is listed in Table 3-13.

Table 3-13. Equipment Required For DC V Optional Tests

Equipment

DMM

RMS Differential Voltmeter

Power Decade Resistor

Differential Amplifier Plug-In

Oscilloscope Mainframe

DC Voltage Reference Standard Reference Divider

Null Detector

Kelvin-Varley Divider

Model

Wavetek 1281 or HP 3458A Fluke 5790A

Clarostat 240C

Tektronix 7A22

Tektronix 7000 Series

Fluke 732B

Fluke 752A

EM Electronics N11(Fluke 845A) Fluke 720A

3-32. DC Voltage Load Regulation Test

Use Table 3-34 for a test record. Proceed as follows to test the dc voltage load regulation:

1.Ensure the Calibrator is in standby. With the test setup of Figure 3-5, connect the power decade resistor across the Calibrator OUTPUT terminals. Connect two shorting links between the Calibrator SENSE and OUTPUT terminals and select external sense (EX SNS indicator lit).

2.Set the reference divider to 10V. Set the Calibrator output to 10V dc. Set the power decade resistor to 199Ω. Set the Calibrator to operate. Adjust the Calibrator as necessary to obtain a null on the null detector. Rotate the most significant dial on the

power decade resistor to 9. Verify that the null detector indication changes less than ±2 μV. Set the Calibrator to standby.

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