Agilent Technologies B1500A User Manual page 9

• Source/Monitor Terminals
Source/monitor unit, SMU, can simultaneously perform DC voltage or current
output and measurement. Typical SMU has the Force, Guard, Sense, and Circuit
Common terminals as shown below. Normally the Force, Guard, and Sense
terminals 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 for the
Kelvin connection which is effective for high current measurement and low
resistance measurement. For the non-Kelvin connection to ease the connections,
connect Force only. Do not connect Sense. It must be opened.
Guard should be extended to around the device terminal for reducing leakage
current caused by a coaxial cable used. Guard must be never connected to
anything at the device side.
Circuit Common should be connected to shielding of the coaxial cable used.
The following image is the Kelvin triaxial connector of Agilent B1500A's HPSMU.