Keithley 2601 Reference Manual

3-12 Return to Section Topics 2600S-901-01 Rev. C / January 2008
Section 3: DUT Test Connections Series 2600 System SourceMeter® Instruments Reference Manual
Guarding and shielding
Source-measure performance and safety are optimized with the effective use of guarding and
shielding (noise and safety shields).
Guarding
A driven guard is always enabled and provides a buffered voltage that is at the same level as the
input/output HI voltage. The purpose of guarding is to eliminate the effects of leakage current (and
capacitance) that can exist between input/output high and low. Without guarding, leakage and
capacitance in the external high-impedance test circuit could be high enough to adversely affect
the performance of the SourceMeter.
Guarding (shown in Figure 3-10) should be used for the following source-measure condition:
• Test circuit impedance is >1GΩ.
NOTE See "Guarding and shielding" in Section 8 for details on the principles
of guarding.
Figure 3-10
CHANNEL A
LO GLO HI G G G HI
SS
KEITHLEY Series 2600
DUT
HILO
Metal Guard
Shield
Guard Shield
The guard shield can be the shield of a
coaxial cable, or it can be an insulated
foil that surrounds the conductor.
>1GW
Models 2602 and 2612 high-impedance guarding

Keithley 2601 Specifications

General

Brand	Keithley
Model	2601
Category	Measuring Instruments
Language	English