Keithley 6430 Instruction Manual page 124

5-16 Source-Measure Concepts
Where within the boundaries the SourceMeter operates depends on the load (DUT) that is
connected to the output. Figure 5-8 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 5-8A, the SourceMeter is sourcing 10V to the 2kΩ load and subsequently mea-
sures 5mA. As shown, the load line for 2kΩ intersects the 10V voltage source line at 5mA.
Figure 5-8B shows what happens if the resistance of the load is decreased to 800Ω. The
DUT load line for 800kΩ intersects the current compliance limit line placing the SourceMeter
in compliance. In compliance, the SourceMeter will not be able to source its programmed volt-
age (10V). For the 800kΩ 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. Con-
versely, 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.