Section 5: Measuring low-resistance devices
Model 2450 Interactive SourceMeter® Instrument User's Manual
5-2
2450-900-01 Rev. A / June 2013
To use the 4-wire connection method:
•
Connect one set of test leads to the FORCE LO and FORCE HI terminals, which force a current
through the device under test.
•
Connect the other set of test leads to the SENSE HI and SENSE LO terminals, which measure
the voltage drop across the DUT.
You can use either the front-panel or rear-panel terminals for this application.
There is no internal connection between protective earth (safety ground) and the LO
terminals of the Model 2450. Therefore, hazardous voltages (more than 30 V
rms
) can appear
on LO terminals. This can occur when the instrument is operating in any mode. To prevent
hazardous voltage from appearing on the LO terminals, connect the LO terminal to
protective earth if your application allows it. You can connect the LO terminal to the chassis
ground terminal on the front panel or the chassis ground screw terminal on the rear panel.
Note that the front-panel terminals are isolated from the rear-panel terminals. Therefore, if
you are using the front-panel terminals, ground to the front-panel LO terminal. If using the
rear-panel terminals, ground to the rear panel LO terminal.
The circuit diagram for the application is shown in the following figure.
Figure 16: Sourcing current and measuring resistance using a 4-wire configuration
