Keysight Technologies B2900 Series, Руководство пользователя

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Keysight B2900 User’s Guide, Edition 5 3-23
Installation
Connecting a DUT
Guarding
Guarding reduces the leakage current between the instrument and a DUT. This is
important when you measure a low current.
Figure 3-10 shows the theory of guarding. The buffer amplifier (

1) keeps the
potential of the Guard conductor at the same potential as the High Force conductor,
so that the current does not flow between the High Force and Guard conductors.
Therefore, the current measured by the instrument is the same as the current at the
DUT terminal because no current is leaked.
For the connection examples shown in Figures 3-7 and 3-8 , the guard is extended to
the test fixture input connectors with triaxial cables.
Figure 3-10 Guarding
CAUTION Never connect the Guard terminal to any output, including circuit common, chassis
ground, or any other guard terminal. Doing so will damage the B2900.
Performing Low Current Measurements
With the default setting, 10 nA and 100 nA measurement ranges are not used. For
the low current measurements, the measurement range settings must be changed.
To change the
measurement
range
1. Press the View key to display the Single view.
If the Range parameters are not displayed in the lower half of the Single view,
press the More, Hide Sweep, Hide Pulse, or Hide Trigger assist key to display
the Range parameters.
2. Change the setting of the Measure Amps field of the Range parameters.
Set AUTO for the auto ranging or FIXED for the fixed range.
Set 10 nA or 100 nA for the minimum or fixed measurement range.
A
Buffer
Guard
High Force
DUT