Agilent Technologies 6680A, 6684A, 6683A, 6681A, 6682A service manual CV Noise Pard

Table 2-4. Constant Voltage (CV) Tests (continued)

Action Normal Result

CV Source Effect (cont)

2

3

4

5

6

7

Set the transformer to the nominal ac line voltage. Connect the DVM across +S and -S(see Fig. 2-1).

Turn on the power supply and program the current to its maximum programmable value and the voltage to its full-scale value (see Table 2-2).

Adjust the load to produce full-scale current (see Table 2-2) as shown on the front panel display.

Adjust the transformer to decrease the ac input voltage to the low- line condition (174Vac or 191Vac). Record the output voltage reading of the DVM.

Adjust the transformer to increase the ac input voltage to the high-line condition (220Vac or 250Vac). Record the output voltage reading on the DVM.

Check test result.

CV annunciator is on. If it is not, adjust the load to slightly reduce the output current until the annunciator comes on.

The difference between the DVM readings in steps 5 and 6 are within the specified Source Effect limits.

CV Noise (PARD)

Periodic and random deviations (PARD) in the output (ripple and noise) combine to produce a residual ac voltage superimposed on the dc output voltage. This test measures CV PARD, specified as the rms and peak-to-peak output voltages over the frequency range of 20Hz to 20MHz.

1

2

3

4

5

6

Turn off the power supply and connect an a-c coupled oscilloscope across the + and -output terminals (see Fig. 2-1). Set the oscilloscope bandwidth limit to 20MHz (30MHz for the Agilent 54504A) and use an RF tip on the oscilloscope probe.

Turn on the power supply and program the current to its maximum programmable value and the voltage to its full-scale value (see Table 2-2).

Adjust the load to produce full-scale current (see Table 2-2) as shown on the front panel display.

Record the amplitude of the waveform.

Replace the oscilloscope connection with an ac rms voltmeter.

Record the reading obtained in Step 5.

CV annunciator is on. If it is not, adjust the load to slightly reduce the output current until the annunciator comes on.

Amplitude is within the specified PARD Peak-to-Peak limits.

Amplitude is within the specified PARD rms limits.

Verification 17