Electrical parameters of Electrolytic Capacitor(II)

4. Leakage current.

The dielectric of the capacitor has a great hindrance to the DC current. However, because the electrolyte is immersed in the aluminum oxide film medium, a very small current called leakage current is produced when applied the voltage and when the oxide film is regenerated and repaired. Usually, the leakage current increases with the increase of temperature and voltage.

5. Ripple current and ripple voltage.

In some data, they are referred to as "ripple current" and "ripple voltage", in fact, ripple current ripple voltage. The implication is that the capacitor can withstand the ripple current / voltage value. They are closely related to ESR and can be expressed in the following terms:

Urms = Irms × R.

VRMS denotes ripple voltage.

Irms indicates ripple current.

R denotes the ESR of capacitors

It can be seen from above that when the ripple current increases, the ripple voltage will increase exponentially even if the ESR remains constant. In other words, when the ripple voltage increases, the ripple current also increases, which is the reason why the capacitance is required to have lower ESR value. After the ripple current is added, the equivalent series resistance (ESRs) inside the capacitor causes heat, which affects the service life of the capacitor. In general, the ripple current is proportional to the frequency, so the ripple current is also relatively low at low frequencies.