Tektronix KEITHLEY SourceMeter 2600B Series User Manual page 80

Section 4: Operation Series 2600B System SourceMeter® instrument User's Manual
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 HI and LO. Without guarding, leakage and capacitance in the
external high-impedance test circuit could be high enough to adversely affect the performance of
the 600B.
Guarding is recommended when test circuit impedance is >1 GΩ.
See "Guard" in the Series 2600B Reference Manual for details on the principles of guarding.
The guard shield can be the shield of a coaxial cable or an insulated foil that surrounds
the conductor.
Figure 34: Connections for guarding
1 Guard shield
2 Metal guard shield
3 Device under test (DUT)
4-20 2600BS-900-01 Rev. A / August 2021