BK Precision 885 Manual De Instrucciones página 35

H
CUR
H
POT
L
POT
L
CUR
(a) CONNECTION
1m 10m 100m 1
(c) TYPICAL IMPEDANCE MEASUREMENT RANGE (£[)
 4-Terminal Path (4TP)
4-Terminal Path connection solves the problem that caused by
the test lead inductance. 4TP uses four coaxial cables to isolate
the current path and the voltage sense cable (Figure 3.5). The
return current will flow through the coaxial cable as well as the
shield. Therefore, the magnetic flux that generated by internal
conductor will cancel out the magnetic flux generated by
external conductor (shield). The 4TP connection increases the
DUT
5T
10 100
A
(d) WRONG 4T CONNECTION
Figure 3.4
32
A
(b) BLOCK DIAGRAM
1K 10K 100K 1M
V
V
10M
DUT
DUT