User manual

2400 Series SourceMeter
®
User’s Manual Ohms Measurements 4-7
Figure 4-3
4-wire resistance sensing
Sense selection
To select sensing mode, press CONFIG then Ω, select SENSE MODE, then
choose 2-wire or 4-wire.
SourceMeter
4-wire Sense HI
4-wire Sense LO
I
Input/Output HI
V
M
V
R
Test Current (I)
Resistance
Under Test
Lead
Resistances
R
S
R
LEAD
R
LEAD
= Current sourced by SourceMeter
= Voltage measured by SourceMeter
= Voltage across resistor
I
V
M
V
R
and measured resistance = =
V
M
I
V
M
Sense Current (pA)
Input/Output LO
R
LEAD
R
LEAD
Because sense current is negligible, =
V
M
V
R
I
V
R