Agilent Technologies 6682A, 6684A, 6680A, 6683A, 6681A service manual CC Load Effect

Table 2-5. Constant Current (CC) Tests (continued)

Action Normal Result

2

CC Noise (PARD) (cont)

Measure the residual noise on the DVM with the power supply turned off. Noise generated by other equipment may affect this measurement and should be removed or factored out.

3

4

5

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

Adjust the load in the CV mode for full-scale voltage (see Table 2-2) as shown on the front panel display.

Observe the reading on the rms voltmeter. Multiply rms voltage by 0.1 to obtain the rms noise current.

The power supply output current should be at its full-scale value and the CC annunciator on. If it is not, adjust the load to slightly reduce the output voltage until the annunciator comes on.

Current is within the specified PARD rms limits (see Table 2-6).

CC Load Effect

This test measures the change in output current resulting from a change in load from full-load voltage to a short circuit. It is recommended that you use averaged readings for Steps 5 and 6 of this test (see Averaging AC Measurements at the end of this chapter).

Note: Refer to Figure 2-4. If you are using Agilent 60504B Eloads, a series DC power source is required to supply the minimum 3 volt input required by the Agilent 60504B Eloads. The series DC source must be capable of 3VDC at a current level greater than the output current of the supply being tested. A switch can be used in place of the series supply if the Eloads are used in place of a load resistor as shown in Fig. 2-4(b).

1

2

3

4

5

6

Turn off the power supply and connect a DVM across the current monitoring resistor (see Fig. 2-3).

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

Set the Electronic Load to CV mode and its voltage to full scale as indicated on its front panel display. Set the series supply for 3VDC and a current greater than that being tested. Series source should be in CV mode.

Observe the DVM reading. Divide this by the resistance of the current monitoring resistor to obtain the output current. Record the result.

Program the Electronic Load input to 3 volts or short the Electronic Load input and repeat Step 5.

Check the result.

Power supply output current is full scale and its CC annunciator is on. If not, reduce the Electronic Load voltage slightly until the annunciator comes on.

You may want to use an averaged reading for this measurement.

You may want to use averaged reading for this measurement.

The difference between the current readings taken in Step 5 and Step 6 must be within specified “Load Effect” limits (see Table 2-2).

20 Verification