Agilent Technologies AGILENT MODELS 6023A and 6028A service manual Constant Current CC Tests

Constant Current (CC) Tests

CCSetup. Constant-current tests are analogous to constant-voltage tests, with the unit's output short circuited and the voltage set to full output to assure CC operation. Follow the general setup instructions.

Load Effect (Load Regulation). Constant current load effect is the change in dc output current (Io) resulting from a load-resistance change from short-circuit to full-load, or full-load to short-circuit. Full-load is the resistance which develops the maximum rated output voltage at current Io. Proceed as follows:

a.Connect the test equipment as shown in Figure 2-3. Operate the load in constant resistance mode (Amps/Volt) and set resistance to minimum.

b.Turn the unit's power on, and turn up voltage setting to full output.

c.Turn up output current to:

10.0Adc (0.010Vdc across Rm) (6023A). Check that the AMPS display reads about 10 amps. 3.3Adc (0.335Vdc across Rm) (6028A) Check that the AMPS display reads about 3.3 amps.

d.Increase the load resistance until the output voltage at +S and -S increases to: 20Vdc (6023A).

60Vdc (6028A).

Check that the CC LED is lighted and AMPS display still reads ≈ current setting.

e.Record voltage across Rm.

f.Short circuit the load.

g.When the reading settles (≈ 10s), record the voltage across Rm again. Check that the two recorded readings differ no more than:

±0.010mVdc (6023A)

±0.0053mVdc (6028A)

h.Disconnect the short across the load.

Source Effect (Line Regulation). Constant current source effect is the change in dc output current resulting from a change in ac input voltage from the minimum to the maximum values listed in the Specifications Table in the Operating Manual. Proceed as follows:

a.Connect the test equipment as shown in Figure 2-3. Operate the load in constant resistance mode (Amps/Volt) and set resistance to minimum.

b.Connect the unit to the ac power line through a variable autotransformer set for low line voltage (e.g. 104Vac for 120Vac).

c.Switch the unit's power on and turn up output voltage setting to full output.

d.Turn up output current to:

29.0Adc (0.029Vdc across Rm) (6023A) 10.0Adc (1.0Vdc across Rm) (6028A)

Check that the AMPS display reads ≈ current setting.

e.Increase the load resistance until the output voltage between + S and - S increases to: 7.0Vdc (603A)

20.0Vdc (6028A)

Check that the CC LED is still on and the AMPS display still reads ≈ current setting.

f.Record the voltage across Rm.

g.Adjust autotransformer to the maximum for your line voltage.

h.When the reading settles record the voltage across Rm again. Check that the two recorded readings differ no more than:

±0.0090mVdc (6023A)

±0.030mVdc (6028A)

PARD Ripple And Noise. Periodic and random deviations (PARD) in the unit's output (ripple and noise) combine to produce a residual ac current as well as an ac voltage super-imposed on the dc output. The ac voltage is measured as constant-voltage PARD. Constant-current PARD is specified as the root-mean-square (rms) output current in a frequency range 20Hz to 20MHz with the unit in CC operation. To avoid incorrect measurements, with the unit in CC operation, caused by the impedance of the electronic load at noise frequencies, use a:

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