Datasheet

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Single-Ended Aluminum Electrolytic Capacitors – ESC, +105°C
Impedance (Z) cont’d
Impedance as a function of frequency (sinusoidal waveform) for different temperature values can be represented as follows
(typical values):
0
.
1
1
1
0
1
0
0
1,000
10,000
0
.
1
1
1
0
1
0
0
1,000
Z
(
o
h
m
)
F
(
K
H
z
)
8
5
°
C
2
0
°
C
10 µF
-
4
0
°
C
R
e
is the most temperature-dependent component of an electrolytic capacitor equivalent circuit. Electrolyte resistivity will
decrease if temperature rises.
In order to obtain a low impedance value throughout the temperature range, R
e
must be as little as possible. However, R
e
values that are too low indicate a very aggressive electrolyte, resulting in a shorter life of the electrolytic capacitor at high
temperatures. A compromise must be reached.
Leakage Current (LC)
Duetothealuminumoxidelayerthatservesasadielectric,asmallcurrentwillcontinuetoflowevenafteraDCvoltagehas
been applied for long periods. This current is called leakage current.
Ahighleakagecurrentflowsafterapplyingvoltagetothecapacitorthendecreasesinafewminutes,forexample,after
prolonged storage without any applied voltage. In the course of continuous operation, the leakage current will decrease and
reach an almost constant value.
Afteravoltage-freestoragetheoxidelayermaydeteriorate,especiallyatahightemperature.Sincetherearenoleakage
currentstotransportoxygenionstotheanode,theoxidelayerisnotregenerated.Theresultisthatahigherthannormal
leakagecurrentwillflowwhenvoltageisappliedafterprolongedstorage.