Keithley SourceMeter 2600 Series Reference Manual page 228

8-22 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 the output. Figure 8-10 shows operation examples for resistive loads
that are 2kΩ and 800Ω, respectively. For these examples, the SourceMeter is
programmed to source 10V and limit 10mA.
In Figure 8-10A, the SourceMeter is sourcing 10V to the 2kΩ load and
subsequently measures 5mA. As shown, the load line for 2kΩ intersects the 10V
voltage source line at 5mA.
Figure 8-10B shows what happens if the resistance of the load is decreased to
800Ω. The DUT load line for 800Ω intersects the current compliance limit line
placing the SourceMeter in compliance. In compliance, the SourceMeter will not
be able to source its programmed voltage (10V). For the 800Ω DUT, the
SourceMeter will only output 8V (at the 10mA limit).
Notice that as resistance decreases, the slope of the DUT load line increases. As
resistance approaches infinity (open output), the SourceMeter will source virtually
10V at 0mA. Conversely, as resistance increases, the slope of the DUT load line
decreases. At zero resistance (shorted output), the SourceMeter will source
virtually 0V at 10mA.
Regardless of the load, current will never exceed the programmed compliance
of 10mA.
2600S-901-01 Rev. A / May 2006 Return to Section 8 topics