FREQUENCY-DEPENDENCE OF CAPACITANCE AND SERIES RESISTANCE OF TA/TA2O5/ELECTROLYTE

Tantalum capacitor manufacturers use highly specific surface anodes, in order to increase specific capacitance. To achieve this, the anodes are made by sintering tantalum powder. The complex anode structure and morphology give rise to a frequency dependence of capacitance and series resistance. In the present work a theoretical model is developed to explain this behaviour. An important conclusion is that the curves of capacitance and series resistance vs. frequency for each anode type are a function of the variable OMEGA which is obtained by multiplying the capacitance at low frequency by frequency and electrolyte resistivity.