Electrolysis of water a small-scale electrolytic cell. It consists of three joined upright cylinders. The inner cylinder is open at the top to allow the addition of water and the electrolyte. A platinum electrode is placed at the bottom of each of the two side cylinders, connected to the positive and negative terminals of a source of electricity. When current is run through the Hofmann voltameter, gaseous oxygen forms at the anode (positive) and gaseous hydrogen at the cathode (negative). Each gas displaces water and collects at the top of the two outer tubes, where it can be drawn off with a stopcock.
Aluminum electrolytic capacitor for better self-healing property of the oxide layer, so that the capacitors have the advantages of both low ESR and low leakage current. The basic material of the anode for aluminum electrolytic capacitors is a foil with a thickness of ~ 20–100 µm made of aluminum with a high purity of at least 99.99%. This is etched (roughened) in an electrochemical process to increase the effective electrode surface. By etching the surface of the anode, depending on the required rated voltage, the surface area can be increased by a factor of approximately 200 with respect to a smooth surface. After