Aluminium Electrolytic Capacitors are the most common types among the Electrolytic capacitors. In these ones, a pure Aluminium foil with an etched surface acts as an Anode. A thin layer of metal, which has a thickness of few micrometers acts as a diffusion barrier, which is placed between two metals to separate electrically. Hence the diffusion barrier acts as a dielectric. The electrolyte acts as a cathode which covers the rough surface of oxide layer.

The following figure shows an image of different sizes of Aluminium Electrolytic Capacitors available.

Depending upon the electrolyte there are three types of Aluminum Electrolytic Capacitors. They are −

• Wet Aluminum Electrolytic capacitors (non-solid)
• Manganese dioxide Aluminum Electrolytic capacitors (solid)
• Polymer Aluminum Electrolytic capacitors (solid)

The main advantage with these Aluminum Electrolytic capacitors is that, they have low impedance values even at mains frequency and they are cheaper. These are mostly used in Power supply circuits, SMPS(Switched Mode Power Supply) and DC-DC Converters.