User Manual
2400 Series SourceMeter
®
User’s Manual Ohms Measurements 4-3
Ohms measurement methods
NOTE For the Model 2430, the following ohms measurement procedures
assume that the DC Mode of operation is selected (“Vsrc” or “Isrc” dis
-
played in the source field). If in the Pulse Mode (“Vpls” or “Ipls” dis-
played), you can select the DC Mode by pressing CONFIG V or I,
selecting the SHAPE menu item, and then selecting DC. Pulse Mode
operation is covered in
Section 5.
There are two methods to measure ohms: auto ohms and manual ohms. When
using auto ohms, the SourceMeter operates as a conventional constant-current
source ohmmeter or DMM. To use this method, simply select an ohms measure-
ment range (or use autorange), and take the reading from the display. When
using auto ohms, the default test current varies with the ohms range, as summa-
rized in Table 4-1.
NOTE You cannot change the test current in the auto ohms mode. If you
attempt to change the source current in auto ohms, the SourceMeter will
display an error message.
With the manual ohms mode, you can select either source V or source I to make
ohms measurements, and the unit will automatically compute the resistance read-
ing using the V/I measurement method. After configuring the desired source and
selecting a voltage or current measuring range, select the Ω measurement
method to display the calculated V/I ohms reading.
NOTE To achieve optimum accuracy, the SourceMeter measures both V and I
and uses these values in ohms calculations (with source readback
enabled). The measured source value is more accurate than the pro
-
grammed source value. For remote operation, the user specifies the
functions to measure. See the resistance measurement accuracy specifi
-
cations in Appendix A.