Keithley 2601B Reference Manual page 243

Series 2600B System SourceMeter® Instrument Reference Manual Section 4: Theory of operation
I-source sink operating boundaries
The quadrant within which the Series 2600B operates depends on the device-under-test (DUT)
connected to the Series 2600B output. The following example illustrates this operation by using the
Series 2600B configured to provide a constant current to discharge a 12 V power source (a battery).
When using the I-Source as a sink, always set the voltage compliance limit to levels that are higher
than the external voltage level. Using the Model 2601B/2602B/2604B to sink more than 3 A can
damage the instrument and invalidate your warranty. Using the Model
2611B/2612B/2614B/2634B/2635B/2636B to sink more than 1.5 A can damage the instrument and
invalidate your warranty.
Figure 100: Sourcing current sink operation example
The voltage compliance limit applies both to positive and negative voltages. For example, if you set
the voltage compliance limit to 15 V, the voltage limit applies to ±15 V.
For this example, the Series 2600B is programmed to source −50 mA (the constant current) and to
limit voltage to 15 V. When the SMU turns on, it begins sinking current as determined by the
programmed I-source level (-50 mA), causing a decrease in the battery voltage. If the battery were
ideal and could be charged negatively, its voltage would then continue to decrease until it is
negatively charged at −15 V (shown by the green arrow in the following figure), at which point the
SMU would be in voltage compliance.
2600BS-901-01 Rev. B / May 2013 4-17