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7
Tutorial
Ground Loops
The signal-generation portion of the Keysight 33210A is isolated from chassis
(earth) ground. This isolation helps to eliminate ground loops in your system and
also allows you to reference the output signal to voltages other than ground. The
illustration below shows the function generator connected to a load through a
coaxial cable. Any difference in ground potentials (V
I
GND
impedance (Z
in the load voltage. However, since the instrument is isolated, there is a high
series impedance (typically 1 MΩ in parallel with 45 nF) in the path to oppose the
flow of I
Ground Loop Effects
356
flow in the shield of the cable, thus causing a voltage drop due to the shield's
). The resulting voltage drop (I
Shield
and thereby minimize this effect.
GND
Keysight 33210A
50W
V
GEN
1 MW
45 nF
Z
Shield
V
OUT
I
GND
V
GND
) will tend to make current
GND
× Z
) appears as an error
GND
Shield
V
R
= V
– (I
L
OUT
GND
L
Keysight 33210A User's Guide
×
Z
)
Shield
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