Series 2600B System SourceMeter® Instrument Reference Manual
Section 4: Theory of operation
2600BS-901-01 Rev. C / August 2016
4-21
Source I
When the instrument is configured to source current (I-source), as shown in the figure below, the
instrument functions as a high-impedance current source with voltage limit capability and can
measure current (I-meter) or voltage (V-meter).
For 2-wire local sensing, voltage is measured at the HI / LO terminals of the instrument. For 4-wire
remote sensing, voltage is measured directly at the device under test (DUT) using the sense
terminals. This eliminates any voltage drops that may be in the test leads or connections between the
instrument and the DUT.
The current source does not require or use the sense leads to enhance current source accuracy.
However, if the instrument is in 4-wire remote sense mode, the instrument may reach limit levels if the
sense leads are disconnected. With 4-wire remote sensing selected, the sense leads must be
connected or incorrect operation will result.
Figure 101: Source I configuration
Source I measure I, source V measure V
The System SourceMeter
®
instrument can measure the function it is sourcing. When sourcing a
voltage, you can measure voltage. Conversely, if you are sourcing current, you can measure the
output current. For these operations, the measure range is the same as the source range.
This feature is valuable when operating with the source in compliance. When in compliance, the
programmed source value is not reached. Thus, measuring the source lets you measure the actual
output level.
