Keysight U1610A - Independently Isolated Scope Input Channels; Figure 1-5 Floating Ground Reference Signal and Earth Ground Reference Signal

1 Getting Started
30 Keysight U1610/20A User’s Guide
Independently Isolated Scope Input Channels
There are two main categories of signal sources:
– Earth ground referenced signal—the voltage signals are referenced to a system
ground, such as earth ground.
– Floating ground referenced signal—a floating signal in which the voltage signal
is not referenced to earth ground.
Figure 1-5 Floating ground reference signal and earth ground
reference signal
When measuring floating signals with instruments that have multiple inputs,
unwanted ground loops may occur. These ground loops can induce measurement
errors and cause electrical shock or power surges. Ground loop occurs between
the negative terminals of two inputs as shown in Figure 1-6.
Instruments with channel-to-channel isolation can be used to eliminate the
ground loops. Isolated channels separate the two signal path effectively from each
other by eliminating any potential common circuit path between the two inputs.
Floating ground
referenced signal
Floating ground
referenced signal
Floating ground
referenced signal
Earth ground
referenced signal
Earth ground
referenced signal
Earth ground
referenced signal