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English
U n d e r s t a n d i n g A C Z e r o I n p u t B e h a v i o r
o f T r u e R M S M e t e r s
Unlike averaging meters, which can accurately measure only pure sinewaves,
True RMS meters accurately measure distorted waveforms. True RMS
converters require a certain level of input voltage to make a measurement.
This is why AC voltage and current ranges are specified from 5% of range
to 100% of range. Non-zero digits that are displayed on a True RMS meter
when the test leads are open are normal.They do not affect the specified AC
accuracy above 5% of range.
Unspecified input levels on the lowest ranges are:
• AC voltage: below 5% of 600mV
• AC current: below 5% of 600mA
C l e a n i n g
Wipe the case with a damp cloth and mild detergent. Do not use abrasives
or solvents. Dirt or moisture in the terminals can affect readings.
