Common Terminal Connection - Keysight B2980B Series User Manual

How to Perform Measurement
Current Measurement
After the mode is changed from Automatic to Manual
The instrument keeps the last used aperture time. And the SPEED function key
shows its value.
Also see

Common Terminal Connection

The Common terminal is internally connected to the common of Ammeter, Analog
Out, and Voltmeter. This terminal is used as the reference terminal for
input/output of them.
For the measurement of the device which has a non-ground potential, the
Common terminal must be connected to chassis ground by using a
Banana-to-Lug cable (furnished) or equivalent. In this condition, the
current/voltage measurement that refers to ground as reference is performed.
For the measurement of the device which has the ground potential, do not
connect any cable between Common and chassis ground. to make the
Ammeter/Voltmeter floating. This condition makes the potential difference
between the input of Ammeter and ground and that may occur an error caused
from the leakage current in low-current measurement. You can reduce an error by
using guarding technique.
Figure 3-5
If a dielectric exists between the Input of Ammeter and the other potential, the
leakage current flows in accordance with a potential difference and resistance.
Guarding technique covers the wire connecting from the Input of Ammeter with a
conductor (Guard) that has same potential as Input to cancel the potential
difference from the surrounding dielectric so that the leakage current can be
92
"Aperture Time" on page
Guarding Technique
Without Guarding
Imeas= Idut+Ileak
A
206.
With Guarding
Imeas= Idut
Idut
Ileak
A
Keysight B2980B User's Guide, Edition 1
Ileak
Idut
Rguard