Filter
Top Products
2 - Installation
24
NOTE: Any voltage drop in the load leads must be subtracted from the full-scale voltage
available at the output terminals.
Coaxial Guard Connections
An active guard connection is available at the output connector. When the guard connection is extended
to a test fixture for example, it can be used to eliminate the effects of leakage current that can exist
between the Hi and Lo output terminals when testing high-impedance devices. In particular, the Hi output
terminal and the Hi sense terminal may benefit from guarding. In this way, any leakage current that is not
load current will be collected by the circuit and not be included in the output current measurement.
The guard connection is always enabled and provides a buffered voltage that is at approximately the
same potential as the Hi output terminal. The output impedance of the guard is approximately 2.1K
ohms.
If you are using tri-axial cables to extend the guard connection to the test fixture, use the center
connector for the Hi connection, the inner shield for the guard connection, and the outer shield as the Lo
connection (see figure 2-5).
GUARD SHIELD
+
_
TRIAXIAL CABLE
TEST FIXTURE
OUTPUT 1
MATING PLUG
SHOWN
Hsen Hi Lo Lsen
INSERT WIRES
TIGHTEN SCREWS
LOCKING SCREW
Figure 2-5. Guard Connections for Test Fixtures