User`s guide

• Source/Measure Terminals
Source/measure unit, SMU, can simultaneously perform DC voltage or current
output and measurement. Typical SMU has the Force, Sense, and Guard terminals
as shown below. Normally the Force, Sense, and Guard are the same potential.
Voltage marked around the terminals indicates the Protection Limits.
Force and Sense must be connected to a terminal of a device under test (DUT) for
the 4-wire connection (Kelvin connection) which is effective for high current
measurement and low resistance measurement. For the 2-wire connection to ease
the connections, connect Force only. Do not connect Sense. It must be opened.
Guard should be connected to the guard shield which covers the DUT high side
wiring for reducing leakage current caused by the wire. Or else, the Guard must be
opened.
Chassis ground (green terminal) should be connected to the ground shield which
covers the DUT including the guard shield to minimize the affect of noise. Or else,
the chassis ground should be opened.
The following image is the source and measurement terminals of Agilent B2900.
For the B2900, the High Force, High Sense, and Guard are the same potential. And
the Low Force and Low Sense are the same potential.
High Sense, for 4-wire connection
High Force
Guard
Chassis ground
Low Force
Low Sense, for 4-wire connection