Averaging the CC Measurements
The CC Load Effect and CC Source Effect tests measure the dc regulation of the power supply's output current. When doing these tests, you must be sure that the readings taken are truly dc regulation values and not instantaneous ac peaks of the output current ripple. You can do this by making each measurement several times and then using the average of the measurements as your test value. Voltmeters such as the Agilent 3458A System Voltmeter can be programmed to take just such statistical average readings as required by these tests.
The following steps show how to set up the voltmeter from its front panel to take a statistical average of l00 readings. 
represents the unlabeled shift key in the FUNCTION/RANGE group.
1.Program 10 power line cycles per sample by pressing 
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2.Program 100 samples per trigger by pressing 
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3.Set up voltmeter to take measurements in the statistical mode as follows:
a. | Press | . |
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b. | Press | until MATH function is selected, then press | . |
c. | Press | until STAT function is selected, then press | . |
4.Now set up voltmeter to read the average of the measurements as follows:
a. | Press | . |
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b. | Press | until RMATH function is selected, then press | . |
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c. | Press | until MEAN function is selected, then press | . |
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5. Execute the average reading program by pressing |
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6.Wait for 100 readings and then read the average measurement by pressing 
. Record this as your result.
