Keithley 2635

2600S-901-01 Rev. C / January 2008 Return to Section Topics 8-21
Series 2600 System SourceMeter® Instruments Reference Manual Section 8: Source-Measure Concepts
Figure 8-15
Comparison of unguarded and guarded measurements
Insulator
I
D
DUT
Metal Mounting Plate
I
L
R
L1
R
L2
Insulator
I
M
= I
D
+ I
L
I
M
= Measured current
I
D
= DUT current
I
L
= Leakage current
IN/OUT
HI
I-Meter
IN/OUT
LO
V-Source
A. Unguarded
I
D
DUT
Metal Mounting Plate
R
L1
Insulator
I
M
= I
D
IN/OUT
HI
I-Meter
IN/OUT
LO
V-Source
x1
GUARD
0V
SourceMeter
SourceMeter
B. Guarded
Connect to earth safety ground
using #18 AWG wire or larger.
Cable Shield
Safety Shield