Chapter 3 Calibration Procedures

Constant Voltage (CV) Verifications

Normal Mode Voltage Noise (CV Ripple and Noise)

The normal mode voltage noise is in the form of ripple related to the line frequency plus some random noise. The normal mode voltage noise is specified as the rms or peak-to-peak output voltage in a frequency range from 20 Hz to

20 MHz.

1 Turn off the power supply and connect the output to be tested as shown in Figure 3-1to an oscilloscope (ac coupled) between (+) and (-) terminals. Set the oscilloscope to AC mode and bandwidth limit to 20 MHz. Connect a resistive load (1.2W for +6V supply and 25W for ±25V supplies) as shown in Figure 3-1(see Table 3-2).

2Turn on the power supply and select the output to be tested using the meter and adjust selection key on the front panel. Enable the outputs and set the display to the limit mode. When the display is in the limit mode, program the current of the selected output to the maximum programmable value and the voltage to the full-scale value (see Table 3-2).

3Check that the front panel CV annunciator remains lit. If not lit, adjust the load down slightly.

4Note that the waveform on the oscilloscope does not exceed the peak-to-peak limit of 2 mV for each of the three outputs.

5Disconnect the oscilloscope and connect an AC rms voltmeter in its place. The rms voltage reading does not exceed the rms limit of 0.35 mV for each of the three outputs.

6Repeat steps (1) through (5) for the remaining outputs.

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Agilent Technologies E3631A manual Normal Mode Voltage Noise CV Ripple and Noise