User`s guide

Agilent 4155C/4156C User’s Guide Vol.2, Edition 6 10-7
Connecting Measurement Devices
Using Connector Plate
To Measure Low Resistance
When you measure a low resistance, high current flows through the DUT. This high
current increases the measurement error caused by the residual resistance of cables.
To cancel the effect of this resistance, you can use Kelvin connections (4-wire),
which means the force and sense lines are extended separately to the DUT. The
Kelvin connection is available for the 4156C’s HRSMU and the 41501A/B’s
HPSMU.
Connect the probing needles to the terminals of the connector plate by using test
leads or coaxial cables. Following instruction uses the coaxial cables:
1. At end of cable, connect coaxial center conductor to force terminal of connector
plate, and connect coaxial outer conductor to guard terminal of connector plate.
2. At another end, connect coaxial center conductor to tail of the probing needle.
Never connect the outer conductor at this cable end.
Extend the outer conductor as close as possible to the probing needle.
3. Repeat 1 and 2 for the sense terminal of connector plate.
4. Contact the probing needles from force and sense terminals as close as possible
to the DUT.
Example
The following example connection can be used to measure low resistance. The sense
line is extended to the probing pad, and contacts the force line through the pad, so
the voltage drop due to the residual resistance caused by cables and test leads is
canceled.
This example uses test leads. To reduce the leakage current, use coaxial cables.