The formation of electrolytic capacitors involves the regeneration of the structure of the aluminum oxide insulator, which is slowly degraded. In some places its surface becomes thinner than it should be, and sometimes it even breaks continuity. After the voltage appears on the plates of such a capacitor, a considerable current begins to flow through it, resulting from the increased leakage, which leads to an effective, but serious damage.

When the voltage is low enough to prevent the insulation layer from being punctured, the oxide layer will rebuild over time and the capacitor returns to normal operation. However, if the degradation has gone too far, a current of such high magnitude will flow through the capacitor that it will burst or, better, the electrolyte will boil and flow out. In both accidents, further operation of such a component is impossible. There may also be a short circuit between the covers.

The capacitor is charged with a stable current of 4mA. Maximum voltage 550V.

Forming a capacitor can take from several tens of minutes to several hours.