Keysight U1281A Guide De L'utilisateur page 55

Using the LPF Function for AC measurements (for U1282A only)
– To avoid possible electric shock or personal injury, do not use the LPF option to verify
WARNING
the presence of hazardous AC voltages. AC voltage values greater than what are
indicated may be present when the LPF is enabled.
– First, make an AC voltage measurement without LPF to detect the possible presence
of hazardous voltages. Then, enable the LPF if required for measurement stability and
response speed.
Your multimeter is equipped with an AC LPF (low-pass filter) to help reduce unwanted
electronic noise when measuring AC voltage or AC frequency. The LPF can improve
measurement performance on composite sine waves.
Table 2-2
Legend
mV
Set up your multimeter to measure AC voltage as shown in Figure 2-2. Press
enable the LPF. Your multimeter continues measuring in the chosen AC mode, but now the
signal diverts through a filter that blocks voltages above 440 Hz (refer to Figure 2-3), as
shown in Figure 2-4.
Figure 2-3
Figure 2-4
Keysight U1281A/U1282A User's Guide
Rotary switch positions allowing AC voltage measurements with LPF
Default function
AC V
V
AC mV
Low-pass filter
Low-pass filter operation
Function when
AC V with LPF
AC mV with LPF
440 Hz
or + Shift
Esc
V mV
Making Measurements
Shift is pressed
Esc
to
Shift
Esc
2
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