Fluke 8021B - Page 36

Eg
=
Source voltage
Rj_
=
Load
resistance +
Source resistance
ly
-
Measured current (display
reading
in mA)
Eg
=
Burden voltage (calculated), i.e., Display reading
expressed as a % of
full-scale
(100
x
r-
)
rUL^bOALt
times
full-scale burden
voltage for selected range. See
Table.
RANGE
MAXIMUM
BURDEN VOLTAGE
2 mA to 200
mA
0.3V
2000
mA
0.9V
current
error
due to
Burden Voltage
En
IN %
=
100 X
5
Eg
-
E
B
.
—
E
B
x
IN mA
-
-=
—
E
S
-Eb
Example: Eg
=
14V, R
L
= 9Q.
ly
=
1497 mA,
1497
E
b
=
100 x^- x
0.9
(from
Table)
=
74.9% x 0.9
=
0.674V
674
.674
Error in %
=
1
00
=
100
=
5.06%
14
-.674
13.326
Increase
displayed current
by
5.06%
to obtain true current.
Error in
mA
=
-674 x 1497
_
1009
_
76
mA
14
-
.674 13.326
Increase displayed
current by 76
mA to obtain true current.
Figure
2-12.
Current
Measurement Error Calculations
2-20