Guarding And Shielding; Guarding - Keithley 2601 Reference Manual

Section 3: DUT Test Connections

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
• Test circuit impedance is >1GΩ.
NOTE See
Figure 3-10
Models 2602 and 2612 high-impedance guarding
3-12
Figure 3-10) should be used for the following source-measure condition:
"Guarding and shielding"
of guarding.
Return to Section Topics
Series 2600 System SourceMeter® Instruments Reference Manual
in Section 8 for details on the principles
2600S-901-01 Rev. C / January 2008