Keithley SourceMeter 2600 Series Reference Manual page 222

8-16 Source-Measure Concepts Series 2600 System SourceMeters Reference Manual
Load considerations
The boundaries the SourceMeter operates in depends on the load (DUT) that is
connected to its output. Figure 8-7 shows operation examples for resistive loads
that are 50Ω and 200Ω, respectively. For these examples, the SourceMeter is
programmed to source 100mA and limit 10V.
In Figure 8-7A, the SourceMeter is sourcing 100mA to the 50Ω load and
subsequently measures 5V. As shown, the load line for 50Ω intersects the 100mA
current source line at 5V.
Figure 8-7B shows what happens if the resistance of the load is increased to
200Ω. The DUT load line for 200Ω intersects the voltage compliance limit line
placing the SourceMeter in compliance. In compliance, the SourceMeter will not
be able to source its programmed current (100mA). For the 200Ω DUT, the
SourceMeter will only output 50mA (at the 10V limit).
Notice that as resistance increases, the slope of the DUT load line increases. As
resistance approaches infinity (open output), the SourceMeter will source virtually
0mA at 10V. Conversely, as resistance decreases, the slope of the DUT load line
decreases. At zero resistance (shorted output), the SourceMeter will source
100mA at virtually 0V.
Regardless of the load, voltage will never exceed the programmed compliance
of 10V.
2600S-901-01 Rev. A / May 2006 Return to Section 8 topics