User manual

4-10 Ohms Measurements 2400 Series SourceMeter
®
User’s Manual
Ohms accuracy of 100mΩ @ 5mA source current, enhanced mode
Source Readback ON, Offset Compensation ON
Ohms accuracy = [Imeas % Rdg accuracy + Vmeas % Rdg accuracy] + System
noise*
Imeasure accuracy = (5mA)(0.035%)
1.75µA
Measured system noise: 00.0000mA
1.75µA+ 00.0000mA = 1.75µA
1.75µA / 5mA = 0.035%
Vmeasure gain accuracy for (100mΩ) (5mA) = 500µV
(500µV) (0.012%) =60nV
Measured system noise: 000.002mV
60nV + 2µV = 2.06µV
2.06µV / 500µV = 0.412%
.035% + 0.412% = 0.447%
100mΩ +/- 0.447%
99.55mΩ to 100.44mΩ
*System noise includes the external connection to DUT. To determine system
noise, the voltage and current noise is measured with test leads connected to the
DUT.
For example, with the 100mΩ resistor connected, the noise voltage was mea-
sured by pressing V measure, selecting the appropriate 200mV range, pressing
the REL button and making note of the systems noise magnitude. In this example,
the measurement was 000.002mV or 2µV.
To measure the current source noise, change the measure function to current
measure, select the appropriate current range (in this case, 10mA), press REL
and note the system noise magnitude. In the example, the system noise current
component was measured as 00.0000mA.