Keithley 6220 Reference Manual page 82

3-4 DC Current Source Operation
When operating as a sink, the Model 622x is dissipating power rather than sourc-
ing it. The polarity of the current and voltage seen at the output is opposite (one
positive, one negative). An external source or an energy storage device, such as a
capacitor, can force operation into the sink region.
Figure 3-1
where it can operate as a source or sink. For both examples, the Model 622x is
programmed to output +10mA. When connected to the 1kΩ resistor and 10V
source as shown in
supplying power to the external test circuit. When the external voltage is
decreased to -30V as shown in
a sink. The Model 622x dissipates 200mW of power (10mA x -20V = -200mW).
Figure 3-1
Source and sink examples
A) Source operation
Operating boundaries
Figure 3-2
ating in the first (I) or third (III) quadrant, the Model 622x is operating as a source.
Figure
positive).
When operating in the second (II) or fourth (IV) quadrant, the Model 622x is oper-
ating as a sink.
positive and voltage negative).
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com
shows examples of the Model 622x connected to an external source
Figure 3-1A, the Model 622x operates as a 200mW source
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shows the four quadrants of operation for the Model 622x. When oper-
3-1A shows an example of quadrant I operation (current and voltage both
Figure 3-1B shows an example of quadrant IV operation (current
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Model 6220/6221 Reference Manual
Figure 3-1B, the Model 622x instead operates as
B) Sink operation
Section 3 topics
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