Precharge Time - Agilent Technologies 4349B Manual

Precharge Time and Wait Time
When setting up the system for measuring the insulation resistance of capacitors, consider the
precharge time and the wait time.
Note
The precharge time of an ideal capacitor is described in this section. Generally,
you should consider characteristics of a dielectric for the estimation of the
actual precharge time.

Precharge time

When the capacitor is charged through precharge register Rp, the precharge time t
calculated as follows (where, Rx
where, C : Capacitance value [F]
x
K : (Test voltage
For example, when Rp is 1 k (=10
time is,
In this example, one precharge stage is enough because t
6-12 Application Measurement
Figure 6-7. Precharge Time
Rp):
2
t = C R
p x p
Charge voltage) / Test voltage
), Cx is 1  F (=10
3
2
t = 10 10
6 3
p
= 2 : 3[ ms ]
2
lnK
F), and K is 0.1, the precharge
6
2
ln 0 : 1
is less than the measurement time.
p
4349B
is
p