Chapter 7 Tutorial
Output Characteristics
156
Figure 7-6. Simplified Diagram of Common Mode and Normal Mode
Sources of Noise
When the load changes very rapidly, as when a relay contact is closed, the inductance
in the hook up wire and in the power supply output will cause a spike to appear at the
load. The spike is a function of the rate of change of the load current. When very rapid
changes in load are expected, a capacitor with a low series resistance, in parallel with
the power supply, and close to the load is the best way to minimize these voltage
spikes.
OUTPUT
TERMINAL
OUTPUT
VOLTAGE
COMMON
MODE
NOISE
<1.5 uArms
NORMAL
MODE
NOISE
R
<5mVpp*
<0.5mVrms*
<8mVpp**
<1mVrms**
*E3646A/48A models
**E3647A/49A models