An Aluminum Solid Electrolytic Capacitor

A new aluminum solid foil type capacitor, based on the use of semiconductor material (manganese dioxide) instead of the use of a liquid electrolyte, is described. This capacitor compares favorably with the high reliability liquid-impregnated aluminum types (the so-called extended life types). This new capacitor occupies an intermediate position, as regards capacitance-voltage product per unit of volume, between the above mentioned high reliability type and the solid slug tantalum type. Outstanding properties of this aluminum capacitor are its behavior at low temperature and the stability of the various electrical parameters during life tests. Because of its estimated lower cost as compared with the solid slug tantalum capacitor, this new type will be especially suited for applications where neither the utmost miniaturization nor the better electrical properties of the solid slug tantalum capacitor are needed, but where a conventional liquid impregnated type has inadequate low temperature characteristics and has too short a stable life. Pilot plant production has been started, the output of which is being used for evaluation purposes.