Fluke 8021B - Measurement Techniques

8021
B
10. Depress
both
the
AC/ DC
switch and the
750V
ac range
switch. Set the
mA/V-H switch
to the
voltage (out) position.
WARNING
THE LOCAL LINE VOLTAGE IS MEASURED IN THE FOLLOWING STEP. BE
CAREFUL
NOT
TO TOUCH THE PROBE TIPS WITH YOUR FINGERS, OR TO
ALLOW THE PROBE
TIPS TO CONTACT EACH OTHER.
I
!. Measure the local ac
line
voltage at
a
convenient output
receptacle. The
voltage should be display
with I
volt
resolution.
12. If the 802! B has
responded
properly to this point,
it is
operational and
ready
for
use.
2-29. MEASUREMENT
TECHNIQUES
2-30.
The concluding
paragraphs of
this section offer
you techniques that
improve
the
measurement accuracy
of your 8021
B. While these
techniques are in general use
throughout the electronics
industry, these
paragraphs
offer specific information for use
with your
80218.
2-31. AC Measurement
2-32.
The ac
ranges of
the
802
i B
employ an
average responding ac converter. This means
that
the unit measures
the
average value of
the input and displays the
measurement
as an
equivalent rms value
for
a
sine
wave. As a resuit,
measurement errors are introduced if the
input wave
form is
distorted
(non-sinusoidal). The
amount of error depends upon the
amount of
distortion.
Figure
2-10 shows the relationship
between sine, square, and
triangular waveforms,
and the
required
conversion
factors.To convert
the display
reading
for a given input
waveform
to
a
known
measurement value, multiply
the reading by the
appropriate Display
Multiplier.
2-33.
Voltage AC/DC
2-34.
The 8021 B is equipped
with five ac and
five
do
voltage ranges; 200
mV, 2V, 20V,
200V, 750V ac/
1000V
dc. All
ranges present an input
impedance oi 10 MO. On the ac
ranges, this
is shunted by less than 100
pF. When making
measurements, be careful not to
exceed
the
overload limits given
earlier in Table
2-2.
2-35. Measurement
errors, due to
circuit loading, can result when makingeither acordc
voltage
measurements
on circuits with high
source resistance. However, in most cases the
error
is
negligible
(sS0.l%) as long as the
source resistance of the measurement circuit is 10
kO or less.
If
circuit loading does
present a problem, the percentage of error can be
calculated
using the
appropriate formula in
Figure
2-11.
2-38.
Current AC/DC
WARNING
INSTRUMENT DAMAGE AND
OPERATOR INJURY MAY RESULT IF THE
FUSE BLOWS
WHILE CURRENT IS BEING
MEASURED IN A CIRCUIT
WHICH EXHIBITS
AN OPEN CIRCUIT VOLTAGE
GREATER
THAN
600V. DO
NOT ATTEMPT AN
IN-CIRCUIT CURRENT MEASUREMENT
WHERE THE
POTENTIAL IS GREATER THAN
600V DC OR RMS AC.
2-16