WARNING:
USE EXTREME
CAUTION lN USE
OF
THIS
DE-
VICE. IMPROPER
USE OF THIS DEVICE
CAN RESULT IN
INJURY
OR DEATH.
FOLLOW ALL
SAFEGUARDS
SUG.
GESTED IN THE
OWNER'S MANUAL IN ADDITION
TO NOR-
MA!
SAFEW PRECAUTIONS
IN DEALING WITH
ELECTRI-
CAL CIRCUITS. DO NOT
USE THIS DEVICE IF
YOU ARE
UNFAMILIAR WITH ELECTRICAL
CIRCUITS AND TESTING
PROCEDURES.
NOT FOR
COMMERCIALOR INDUSTRIAL
USE.
WHAT
DOES'TRUE RMS' MEAN?
RMS
stands lor Root-Mean-Square. RMS is a
standard
method
for
determiriing the effective
value
of
a
varying or alter-
nating voltage. The
RMS value is the DC voltage that would
produce
the same amount ol
heat
as the
voltage
you
are
measuring,
if
you
were
to apply both
voltages
across
identical
resistors.
The true RMS value is helpful when
you
need
to
measure
an
AC
voltage
that
is not
a
pure
sine
wave. Most meters uS€
oVOr.
ageresponding AC converters. These meters are calibrated
with
pure
sine waves. lf
you
measure a sine wave that does
not have harmonic
distortion, the
m.eter
gives
an
accurate
reading.
But, if
the sine
wave is not
pure-there
are distor-
tions within
the
waveform, or
you
measure triangle waves or
square waves
-
the average.responding
meters display an
in-.
',8
For
example, a 2-volt
peak-topeak,
500/o duty cycle square:
wave
measures correctly as 1.000 VAC on
this
meter. An aver-
-age
responding meter
displays
1.111 VAC-an
error of
more
than 11
percentl,
The
maximum frequ'ency
your
meter
can accurately
measure
is
5000
Hz
lor AC voltrage
and
1000 Hz lor
AC current.
The
al-
lowable
crest factor is 1:1 to
3:1.
The
crest
factor is
the
ratio
ol
the
peak
signal value divided by the RMS value. A 10%
duty
cyole
square
wave
with a
peak
voltage of
3
volts has
an
RMS
value
ol about
.95
volts. This
gives
a
crest factor
of 3.16
(3V/
.95V),
and is
outside this
meter's
range of accuracy.
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