Agilent Technologies 4349B, Manual

Page: 85 / 233

4349B
Theory of Operation
This section provides the 4349B 's theory of operation.
Overall Measurement Theory
The 4349B measures the resistance of the Device Under T est (DUT) in the following manner .
Figure 3-6. Simplied Model of the 4349B
Figure 3-6 shows the simplied model of the 4349B measuring a DUT . In Figure 3-6, a DUT
is connected in series with test voltage source V, and ammeter A. Ri is the 4349B's input
resistance (R i = 1k ).
In the current measurement mode (the measurement parameter is I), the 4349B displays the
actual current I for the measurement result. F or example , if R is 100 k, and V is 1 V, the
measurement result will be 9.9 A (
1
100 k +1k
).
In the resistance measurement mode (the measurement parameter is R), the 4349B displays the
\derived" DUT resistance , R, which coincides with the actual DUT resistance . In other words ,
if the ammeter measures I when the source voltage is V, the 4349B displays the DUT resistance
R, calculated using the following equation:
R =
V
I
0 R i
Function Reference 3-19