Electrolytic capacitors

Developments in electrolytic capacitors during the past 20 years are reviewed. Fundamental investigations on anodic-oxide dielectrics are providing a basis for a better understanding of the behaviour of the capacitors but there are still many points of dispute. Use of these dielectrics under wider ranges of conditions has disclosed many new forms of electrical breakdown. The thinness of the dielectric films necessitates the use of special techniques for the study of their structure. Changing requirements have resulted in the appearance of many new forms of electrolytic capacitor. There has also been a marked improvement in the performance of the existing aluminium types. Possible new developments are indicated.