Fluke 5725A - Manual (Page 35)

Introduction and Specifications
Resistance Specifications
1
1-19
Table 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
1 k
1.9 k
10 k
19 k
100 k
190 k
1 M
1.9 M
10 M
19 M
100 M
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 x10
-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 w i th i n the 5720A. Use the follow i ng
equat i on to determ i ne the error, and add th i s error to the correspond i ng uncerta i nty or stab i l i ty
spec i f i cat i on.
Error = K( I
L
- I )/( I
L
x I )
Where: Error i s i n m
Ω
for all two-w i re comp values and four-w i re short, and i n ppm for the rema i n i ng
four-w i re values.
K i s the constant from the above table;
I and I
L
are expressed i n mA for short to 1.9 k
Ω
;
I and I
L
are expressed i n
µ
A for 10 k
Ω
to 100 M
Ω
2. For I
U
< I < I
MAX
errors occur due to self-heat i ng of the res i stors i n the cal i brator. Use the following
equat i on to determ i ne the error i n ppm and add th i s error to the correspond i ng uncerta i nty or stab i l i ty
spec i f i cat i on.
Error i n ppm = K( I
2
- I
U
2
)
Where: K i s the constant from the above table;
I and I
U
are expressed i n mA for short to 19 k
Ω
;
I and I
U
are expressed i n
µ
A for 100 k
Ω
to 100 M
Ω