Burden Voltage Error; Test Lead Compensation; Diode Test Operation - Fluke 8010A Instruction Manual

OPERATION
APPLICATIONS
DIODE TEST
(kO,
1.
DE-ENERGIZE CIRCUIT TO BE
MEASURED
2.
SELECT Range
{2
-4- range
preferred)
3.
SELECT FUNCTION
:
4.
CONNECT
TEST LEADS
HIGH
(+)
LOW
(-}
,
FORWARD
BIAS:
I-
Figure
2-9,
Diode Test Operation
2-43.
Burden
Voltage Error (Current)
2-44.
When
a multimeter
is
placed
in series
with a
circuit
to
measure
current, the voltage
drop
of the multimeter
induces
an
error.
This voltage
is
called the
burden
voltage.
The
maximum
full-scale
burden
voltages for your
Multimeter
are 0.3
V
for the four lowest ranges
and
0.9V
for the highest range.
2-45.
These voltage
drops can
affect
the accuracy of the
current
measurement
if
the current source
is
unregulated
and
the resistance
of
the
shunt and
fuses of the multimeter
exceeds
1 /
1000 of the source
resistance.
If
the
multimeter
burden
voltage
is
significant,
the
formula
in
Figure 2-11
can be used
to calculate
the
burden
voltage
error.
2-46. Test
Lead Compensation
(Resistance)
2-47.
When
measuring low
resistances, the effects of
test
lead resistance
may
add a
significant error.
This error
is
compensated
for
by measuring the lead resistance
and
subtracting
it
from
the resistance
measured
in the
circuit.
The
test
lead resistance
of the
8010A must
be subtracted
manually,
by the operator, to
compensate
for this error.
The 8012A
provides a
ZERO
function, for
Low Ohms
resistance
measurements, that "zeros out" the value of the
test
lead resistance.
Figure 2-7
and
the
paragraphs
on
Low Ohms
Resistance describe
how
to
use
the
ZERO
function of the
8012A.
2-48.
Use
the following procedure, to
manually
compensate
for
test
lead
resistance:
1.
Setup the
Multimeter
as
shown
in
Figure
2-6.
Short the
test leads
together (press the
test
leads
together firmly).
2-9