High Resistance Measurements; Leakage Resistance Measurements; Dc Voltage Measurements; Ac Voltage Measurements - Fluke 8010A Instruction Manual

OPERATION
APPLICATIONS
3.
Record
the
Multimeter reading obtained
in
Step
2.
4.
Proceed with the resistance
measurement and
subtract the value of Step
3
from
the
Multimeter reading.
1.
DC
VOLTAGE MEASUREMENTS
Loading Error
in
%
=
1
00
x
Rs
-r
(
Rs +
1
0^
Where: Rs = Source
resistance
in
ohms
of
circuit
being
measured.
2.
AC VOLTAGE MEASUREMENTS
First,
determine input impedance,
as
follows:*
10"^
Zin =
^
VI
+
{2
tr
F
•
Rin
'
Cin)^
Where: Zin
=
effective input impedance
Rin = 10*^
ohms
Cin =
1
00 X
1
0"^
^
Farads
F
=
frequency
in
Hz
Then, determine, source loading
error
as
follows:'
Loading
Error
in
%=
100 X
'
+
Zin
Where:
Zs = source
impedance
Zin
= input
impedance
(calculated)
*Vector algebra required
Figure 2-10. Circuit Loading
Error
2-49.
High Resistance Measurements
(Conductance)
2-50.
The
conductance
function of
your Multimeter can
be used
to
measure
high
resistive
(low
leakage)
components
(diodes
and
capacitors) while minimizing
noise problems.
The
three
conductance
ranges
(2
mS,
20
juS,
and
200 nS) can be used
for
making
resistance
measurements from
5000
to
I
MO,
50
kO
to 100
MO,
and
5
MO
to 10,000
MO.
Refer
to
Figure 2-12
for a
list
of
conductance
to resistance conversions.
2-51.
Leakage
Resistance
Measurements
(Conductance)
2-52.
Use
the conductance function
for leakage
testing
on
purely
resistive
components
(e.g.,
cables
and
pcb's).
NOTE
Under high humidity
conditions, fingerprints
and
other residual surface
contaminants can
create their
own
leakage paths.
Clean
all
surfaces
and
use clean
test
leads
to
minimize
the
effect
of leakage paths.
2-53.
Diode Leakage
Tests (Conductance)
2-54.
Diode
leakage
(Ir) tests
require that the diode
junction be
reverse biased while being measured.
Connect
the
anode of the diode
to the
COMMON
input connector
to reverse bias a diode junction.
A
good
silicon
diode
will
produce an
in-scale
display reading on
the 200
nS
range
when
reverse biased.
Es
=
Source
voltage
Rl
=
Load resistance
+
Source resistance
tm
=
Measured
current (display
reading
in
amps)
Eb
=
Burden voltage (calculated)
Eb
=
meas. current [(200/current range
in
mA}
+.35]
Error
in
%
=
100 x Eb/(Es
-
Eb)
Error
in
A
=
(Eb
x lm)/(Es - Eb)
EXAMPLE;
Es
=
15V
Rl
=
100
kO
Im
=
148.51 tuk (.14851
mA)
Eb
=
148.51 X
10-'
X
[(200/.2)
+
.35]
=
148.51 X 10 X 1000.35
=
148.56
mV
Max.
error
in
% =
100
x [148.56
mV/(15V
- ,14856V)]
=
1.0003%
Add
this to
the
range
spec, accuracy:
Max.
error
in
% =
1.0003% ±(.2%
+
2
digits)
Max. error
in
A =
(148.56
mV
x 148.51 ;;A}/(15000
mV
- 148.56
mV)
=
1
.486
Add
1.486 yvA to
the reading
for correct current
2-10
Figure 2-11.
Calculating
Burden
Voltage
Error