4-16
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2600AS-901-01 Rev. B / September 2008
Section 4: Source-Measure Concepts
Series 2600A System SourceMeter® Instruments Reference Manual
Source V
When configured to source voltage (V-Source) as shown in
, the SourceMeter
instrument functions as a low-impedance voltage source with current limit capability and can
measure current (I-Meter) or voltage (V-Meter).
Sense circuitry is used to continuously monitor the output voltage and make adjustments to the
V-Source as needed. The V-Meter senses the voltage at the input/output terminals (2-wire local
sense) or at the DUT (4-wire remote sense using the sense terminals) and compares it to the
programmed voltage level. If the sensed level and the programmed value are not the same, the
V-Source is adjusted accordingly. Remote sense eliminates the effect of voltage drops in the test
leads ensuring that the exact programmed voltage appears at the DUT.
The voltage error feedback to the V-Source is an analog function. The source error amplifier is
used to compensate for IR drop in the test leads.
Figure 4-10
Source V configuration
Measure only (V or I)
shows the configurations for using the SourceMeter instrument exclusively as a
voltmeter or ammeter. As shown in
, the SourceMeter instrument is configured to
measure voltage-only by setting it to source 0A and measure voltage.
Remote
SENSE HI
IN/OUT HI
Remote
I-Meter
IN/OUT LO
V-Meter
Sense Output
Adjust V-Source
(Feedback)
SENSE LO
Local
Local
x1
GUARD
+
V-Source
1
2
1
2
NOTES: 1. This represents a protection circuit that is very
high impedance until the voltage across it exceeds
approximately 3V. Above 3V, the protection turns
on and allows current to flow through it.
2. Approximately 13k
W
.
