The primary objective of this thesis is to determine and analyze the failure mechanisms of solid tantalum capacitors, pinpoint the causes, and suggest the precautionary measures that prevent the occurrence of these failures. To achieve this goal, the study went in two directions, theoretical and experimental. The theoretical part-is a comprehensive review of the work -done on tantalum capacitors since 1960 up to date.

The experimental part of the study is a life test (1000 hours) of solid tantalum capacitors under humidity and high temperature. To avoid the misconception that could happen by investigating a particular manufacturer's product, units from five international companies are tested. For each unit, three parameters are measured before and after the life test; namely capacitance, equivalent series resistance (ESR), and leakage current. Both humidity and temperature were found to have profound effects on capacitor behaviour.

The study was also able to rank the five major capacitor producers according to their units behaviour before and after the life test.