User`s guide

Chapter 3 Calibration Procedures
Common Mode Current Noise
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3
3 The output current should be at the full rated rating with the CC annunciator on. If
not lit, adjust the load so that the output voltage drops slightly until the
CC annunciator
lights.
4 Divide the reading on the rms voltmeter by the load resistance to obtain rms current.
The readings should be within the limit of 2 mA.
Common Mode Current Noise
The common mode current is that ac current component which exists between the
output or output lines and chassis ground. Common mode noise can be a problem for
very sensitive circuitry that is referenced to earth ground. When a circuit is referenced
to earth ground, a low level line-related ac current will flow from the output terminals
to earth ground. Any impedance to earth ground will create a voltage drop equal to
the output current flow multiplied by the impedance.
1 Turn off the power supply and connect a 100 kΩ resistor (R
S
) and a 2200 pF capacitor
in parallel between the (-) terminal and chassis ground.
2 Connect a digital voltmeter across R
S
.
3 Turn on the power supply. Select the 8V/20A* or 25V/7A** range, enable the output,
and set the display to the limit mode. When the display is in the limit mode, program
the output to the full rated value (8.0 V and 20.0 A)* or (25.0 V and 7.0 A)**.
4 Record the voltage across R
S
and convert it to current by dividing by the resistance
(DVM reading/100 k
Ω). Note that the current is less than 1.5 μA.
*For Agilent E3633A Model **For Agilent E3634A Model