Agilent Technologies 4339B, Operation Manual

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4339B High Capacitance DUT Measurement
Figure 7-3 shows the measurement conguration for this application.
Figure 7-3. Capacitance Measurement Conguration
Where ,
Rs Output Resistance of the 4339B
Rx P arallel resistance of the DUT
Cx P arallel capacitance of the DUT
Ri Input resistance of the 4339B
Ro A dditional Series Output Resistance of the 16339A
Necessary charging time is approximately led by following equation.
t
c
= 0 2 l n(
X
100
2
R
s
+ R
i
+ R
o
R
x
)
Where ,
t
c
: Charge time [s]
X : Measurement Error [%]
= C
x
2 (R
s
+ R
i
+ R
o
)
Generally , when measuring these types of DUT's as described in this section, you should expect
a charging time of more than 10 or 20 times .
Note
The charge time of an ideal capacitor is shown in this section. Generally , you
should consider characteristics of a dielectric for the estimation of the actual
charge time .
Note
When the additional series resistor value is too high, its resistance can not be
disregarded and it causes additional measurement error .
Measurement Basics 7-7