Dielectric Materials for Electrical Engineering

Chapter 18

Electrolytic Capacitors 1

18.1. Introduction

Considering their ability to store energy in the form of electrostatic charges, capacitors are indispensable passive components in electronic and electronic power circuits. The physical and geometrical properties of the dielectric which constitutes them have a major impact on their characteristics.

Electrolytic capacitors are amongst the most commonly used capacitors because they associate a strong capacity with unit volume, an operating voltage which can reach several hundred volts and an attractive price. Their main fault is their relatively high rate of failure compared with the other constituents of electronic circuits. The presentation of different constituents, their foils and the technology used for the manufacture of these capacitors allows us to understand and deduce their main characteristics. Owing to the elaboration of equivalent electrical diagrams related to the different elements making up the capacitor, the behavior of this latter and the influences of electrical parameters, temperature or ageing can be analyzed.

This chapter starts with a presentation of parameters influencing the characteristics of capacitors, which permits an inventory to be made of their different families. The most used electrolytic capacitors are those with liquid electrolyte aluminum or solid electrolyte tantalum. The principle, the constituents and the foils of these two components are detailed. The models and the characteristics for ...