B&K 281 - Measuring DC Currents; DC Current Safety Precautions; Measuring AC Currents; Measuring Resistance

ar
қ.
элг, '
+ TURNING INSTRUMENT ОМ
à
бес
FUNCTION
switch
1
to
the
OFF
position.
coded
the
line
cord
to
a
117
volt,
50/60
Hz
source.
ec
the
test
probe
assembly
11
to
the
meter.
Insert
the
dual-pin
D.
the.
(+)
pin
is
inserted
in
the
(7)
jack
6
and
the
(—)
pin
is
inserted
in
the
COM
jack
5.1
it
is
desired
to
measure
current
"dn
Ше
1
ampere
rangesthe
(+)
pin
is
connected
to
the
1
A
jack
4.
d.
Turn
the
instrument
on
by
rotate
the
FUNCTION
switch
to
the
OHMS
posi
ion.
;
24.
е;
Without
a
ee,
cted
across
the
test
leads,
the
overrange
indication
should
occu
causing.
e
first
digit
to
be
blanked
and
the
second
and
third
|
digits
to
flash
on
and
off
together.
Shorting
the
rn
id
leads
should
produce
a
zero
readi
g
(first
digit
off
and
a
“0”
display
on
the
second
and
third
px
rich
100K
probe
resistor
out.
.
DC
VOLTAGE
"MEASUREMENTS
~.
a.
Set
FUNCTION
switch
I
to
the
4-DCV
position
if
the
voltage
to
be
measured
is
positive
with
respect
to
common
reference
point,
or
to
the
—DCV
position
if
the
voltage
to
be
measured
is
negative
with
respect
to
a
common
reference
point.
Make
sure
that
the 100
Kohm
resistor
in
the
test
probe
is
switched
out,
viles
requie
to
provide
isolation
when
measuring
d-c
voltages
in
a
high
frequency
circuit.
b.
Set
RANGE
switch
3
as
required
for
the
voltage
amplitude
to
be
measured.
If
the
magnitude
of
the
voltage
is
not
known,
set
the
RANGE
switch
to
the
highest
position
and
reduce
the
settings
as
required
to
obtain
a
satisfactory
reading.
c.
Connect
the
negative
clip
lead
of
the
test
probe
assembly
11
to
the
common
point
of
the
chassis
or
equipment
in
which
the
measure-
ments
are
to
be
performed.
d.
Touch
the
tip
of
the
probe
to
the
voltage
point
to
be
measured.
A
reading
will
be
obtained
if
the
polarity
of
the
voltage
corresponds
to
that
selected
by
the
FUNCTION
switch.
If
the
polarity
is
re-
versed,
the
polarity
sensing
circuit
will
be
energized,
causing
the
first
digit
to
stay
on
and
the
second
and
third
digits
to
remain
off.
Reset
the
FUNCTION
switch
to
the
polarity
position
required
to
obtain
a
reading.
e.
If
the
amplitude
of
the
DC
voltage
measured
is
greater
than
twice
that
of
the
range
selected,
the
overrange
indication
will
become
operative
and
the
first
digit
of
the
display
will
remain
off
and
the
second
and
third
digits
will
flash
on
and
off
together.
The
RANGE
switch
should
then
be
adjusted
to
a
higher
range
as
required
to
obtain
a
satisfactory
reading.
f.
Refer
to
Table
1
for
correct
interpretation
of
the
reading
displayed.
. AC VOLTAGE MEASUREMENTS
a. Place the FUNCTION switch in the ACV position.
b. Switch out the 100 Kohm resistor in the test probe.
9
йыз