Keysight U1271A - Figure 2-3 AC Voltage with LPF Display; Using the LPF (Low Pass Filter) Function for AC Measurements

Making Measurements 2
Measuring AC Voltage
U1271A/U1272A User’s Guide 59
Using the LPF (Low Pass Filter) Function for AC
measurements
Your multimeter is equipped with an AC low pass filter to
help reduce unwanted electronic noise when measuring AC
voltage or AC frequency.
1 Rotate the multimeter’s rotary switch to / .
2 Press to activate the low pass filter function ( ).
Your multimeter continues measuring in the chosen AC
mode, but now the signal diverts through a filter that
blocks unwanted voltages above 1 kHz.
Figure 2-3 AC voltage with LPF display
The low pass filter can improve measurement performance
on composite sine waves that are typically generated by
inverters and variable frequency motor drives.
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WARNING
• To avoid possible electric shock or personal injury, do not use the
Low Pass Filter option to verify the presence of hazardous AC
voltages. AC voltage values greater than what are indicated may
be present when the Low Pass Filter is enabled.
• First, make an AC voltage measurement with the filter OFF to
detect the possible presence of hazardous voltages. Then, select
the filter function if required for measurement stability and
response speed.