52 BELL SYSTEM TECHNICAL JOURNAL 



The Anode Construction and Material 



The construction of the electrodes is shown in Fig. 7. The positive 

 electrode on which the dielectric film is formed is made of four corru- 

 gated aluminum plates, each supported by four integral ears. In an 

 assembled condenser the positive plate surfaces are entirely immersed 

 in electrolyte, the ears extending up through the oil and providing 

 contact with the positive terminal. 



Fig. 7 — Aluminum electrolytic condenser, showing construction of the electrodes 



The material for the positive plates is aluminum of special com- 

 position, selected on a basis of properties which influence the formation 

 of the film, the leakage current and the life of the metal. In general, 

 the higher the purity of the aluminum the more rapid is the formation 

 of the film and the lower is the resultant leakage current. 



It has been noticed that the unit-area capacity for high-purity 



