Aluminum electrolytic capacitors comprise a voltage range from a few volts up to approximately 700 V and offer a wide capacitance range from 1 µF up to about 1 F whilst having a compact construction at the same tim. Defects in the dielectric of the anode are a major cause of the leakage current observed with electrolytic capacitors. Defects result from manufacture-related damages (cuttin. The leakage current specified in the data sheet shall be valid even after a long, voltage-free storage period, giving it a much higher numerical value than the operating leakag. In a series connection of capacitors, the voltage across the capacitors splits according to the ratio of insulation resistances of the capacitors (or in relation to the reciprocal l. For a parallel connection of several branches of electrolytic capacitors connected in series, another question arises for the topology of the balancing circuit: are all bra.
[PDF Version]
It should be noted that the leakage current indicated by the capacitor manufacturer is not the true leakage current, but the current including the absorption current. The higher the applied voltage, the larger the leakage current, and the leakage current increases rapidly when the rated voltage is exceeded.
What causes leakage current in aluminium electrolytic capacitors?
In aluminium electrolytic capacitors, leakage current is primarily caused by imperfections in the oxide layer. This current varies mainly depending on the applied voltage, time, and capacitor temperature. Electrolytic capacitors have large leakage currents while plastic and ceramic capacitors have very small leakage currents.
What is a leakage current rating of an electrolytic capacitor?
Leakage current can cause the capacitor to lose charge over time and can lead to premature failure. The leakage current rating of an electrolytic capacitor is the maximum amount of current that it can tolerate without degrading its performance.
How does voltage affect the DC leakage current of a capacitor?
The DC leakage current of a capacitor is greatly dependent on the applied voltage. For aluminium electrolytic capacitors, this current increases with an increase in operating voltage. As the operating voltage exceeds the rated voltage and approaches the forming voltage, the leakage current increases exponentially.
How to minimize the leakage current of an electrolytic capacitor?
To minimize the leakage current of an electrolytic capacitor, it is important to choose a capacitor that has a high-quality dielectric layer and a low impurity level in the electrolyte. The choice of materials used in the capacitor construction can also affect the leakage current.
How does self-healing affect the leakage currents of aluminium electrolytic capacitors?
The self-healing process has a significant effect on the leakage currents of aluminium electrolytic capacitors. Time dependence of leakage currents is also caused by forming of the dielectric material. Other parameters that determine the value of this small current include the type of electrolyte, capacitance, and forming voltage of the anode.