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8024B
8024B
2-53.
Conductance-to-Resistance Conversion
2-54.
The
conductance measurement
function of
your
8024R
displays
in
siemens.
To
convert siemens
to
ohms,
use
either the
conversion
scale
and
interpolation tabic
in
Figure
2-14 or
the
formula: siemens
—
I
/ft.
2-55.
AC
Measurements
2-56.
The
ac ranges
of
the
8024 B
employ
an average responding ac
converter.
This
means
that the unit
measures
the
average
value of
the input,
and
displays
it
as
an equivalent
rms
value
for a sine
wave.
As
a
result,
measurement
errors are
introduced
when
the
input
wave
form
is
distorted (non-sinusoidal).
The amount
of error
depends
upon
the
amount
of
distortion.
Figure
2-15
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.
2-57.
AC/DC
Voltage
Measurements
2-58.
The 8024B
is
equipped
with
five
ac
and
five
dc
voltage ranges;
200
mV,
2V,
20V,
200V,
750V
ac/
1000V
dc.
All
ranges present an input
impedance
of
10
Mft.
On
the
ac
ranges,
this
is
shunted by
less
than
100
pF.
When
making
measurements,
be
careful
riot
to
exceed
the
overload
limits
given
earlier in
Table
2-2.
2-59.
Measurement
errors
due
to circuit
loading can
result
when making
either
ac or dc
voltage
measurements on
circuits
with high source
resistance.
However,
in
most
cases the
error
is
negligible
(^0.1%)
as
long
as the
source
resistance
of
the
measurement
circuit
is
10
kft
or
less. If
the
circuit
does
present
a
problem,
the
percentage of
error
can be
calculated
using
the
appropriate
formula
in
Figure
2-16.
2-60.
AC/DC
Curreni
Measurements
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
IN-CIRCUIT
CURRENT MEASUREMENT WHERE THE
POTENTIAL
IS
GREATER THAN
600V
DC OR AC
RMS.
2-61.
Four
ac
and
four
dc
curreni ranges
are
included
on
the
8024B; 2
mA,
20 m.A, 200
mA,
and 2000
mA.
Each
range
is
diode protected
to
2
amps
and
fuse
protected
above
2
amps.
If
the
fuse
blows,
refer to
fuse
replacement information
given
earlier in this section.
2-62.
in
high
electrical
noise
environments
(near
ignition
switches, fluorescent
lights,
relay switches,
etc.)
unstable
or
erroneous readings (exceeding
specifications)
may
occur.
The
effect
is
most
obvious
when
measuring low
level
current
on
the
2
mA
range,
if
an
erratic
or
erroneous reading
is
suspected,
temporarily
jumper
the
V/
ft/
S
connector
to the
mA
connector. This
will
ensure
an
accurate
measurement.
Remove
this
temporary
jumper
when
the
measurement
has
been completed. This
is
recommended
only
for the 2
m A
and
20
mA
ranges.
CAUTION
To
avoid possible instrument
damage
and/or erroneous
measurements,
remove
the
temporary V/Q/S-to-mA jumper
before attempting voltage
or
resistance
measurements.
200
-q
Conversion
Scale
nS
•nS-to-MO
200
nS Range
(1000/nS
*
M£2)
100-1=10
'S
= siemens =
1/f2=
International unit
of
conductance
formerly
known
as
the
mho.
50;
20
10
5
2
1
05
02
20
50
100
200
500
1000
2000
5000
01 _i_
ioooo
Find
the
approximate
resistance
value using the
scaie
above.
Then, on
the
table
below,
locate
the
most
significant digit
of the display reading
on
the
vertical
NO.
column, and
the next
digit
on
the horizontal
NO.
row.
The
number
at
the intersecting coordinates represents the
unknown
resistance
value.
For example,
a
reading
of
52.0
nS
is
equal
to
19.2 Ml2.
Decimal
point location
is
determined from
the
scale
approximation.
Interpolation
Table
(I
/no.)
NO.
.0
.1
.2
.3
.4
.5
.6
.7
,8
.9
1
1
.909
.833 .769
.714
.667 .625
.588
.556
.526
2
.500 .476
.455 .435
.417
.400 .385
.370 .375
.345
3
.333 .323
.313 .303
.294
.286 .278
.270
.263
.256
4
.250 .244
.238 .233
.227
.222 .217
.213
.208 .204
5
.200 .196
.192 .187
.185
.182 .179
.175
.172 .169
6
.167
.164
.161
.159 .156
.154 .152
.149
.147 .145
7
.143
.141
.139
.137
.135
.133 .132
.130
.128 .127
8
.125 .123
.122
.121
.119
.118 .116
.115
.114 .112
9
.111
.110
.109 .108 .106
.105 .104
.103
.102 .101
Figure
2-14.
Conducfance-fo-Resistance Conversion
2-24
2-25
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