Fluke 5725A, Инструкция по эксплуатации, Страница: 28 / 196

5725A
Instruction Manual
1-12
Current Derating Factors
Nominal Value Value of Derating Factor K for Over or Under Current
Ω
Two-Wire Comp
I<I
L
(Note 1)
Four-Wire
I<I
L
(Note 1)
Four-Wire
I
U
<I<I
MAX
(Note 2)
SHORT
1
1.9
10
19
100
190
1k
1.9k
10k
19k
100k
190k
1M
1.9M
10M
19M
100M
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
5000
5000






0.3
300
160
30
16
3.5
2.5
0.4
0.4
50
50
7.5
4.0
1.0
0.53
0.2
0.53
0.1

4 X 10
-5
1.5 X 10
-4
1.6 X 10
-3
3 X 10
-3
1 X 10
-2
1.9 X 10
-2
0.1
0.19
2.0
3.8
2 X 10
-5
3.8 X 10
-5
1.5 X 10
-4
2.9 X 10
-4
1 X 10
-3
1.9 X 10
-3

Notes:
1. For I<I
L
, errors occur due to thermally generated voltages within the 5700A. Use the following equation to determine the error, and add
this error to the corresponding UNCERTAINTY or STABILITY specification.
Error = K(I
L
- I)/(I
L
X I)
Where: Error is in m
Ω
for all TWO-WIRE COMP values and FOUR-WIRE SHORT, and in ppm for the remaining FOUR-WIRE values.
K is the constant from the above table;
I and I
L
are expressed in mA for SHORT to 1.9 k
Ω
;
I and I
L
are expressed in
µ
A for 10 k
Ω
to 100 M
Ω
2. For I
U
<I<I
MAX
errors occur due to self-heating of the resistors in the 5700A. Use the following equation to determine the error in ppm and
add this error to the corresponding UNCERTAINTY or STABILITY specification.
Error in ppm = K(I
2
-I
U
2
)
Where: K is the constant from the above table;
I and I
U
are expressed in mA for SHORT to 19 k
Ω
;
I and I
U
are expressed in
µ
A for 100 k
Ω
to 100 M
Ω