Description

Impedance and capacitance spectra (or scattering parameters) are common representations of frequency dependent electrical properties of capacitors. The interpretation of such spectra provides a wide range of electrochemical, physical and technical relevant information. Those need to be separated from the ever-present measurement artifacts as well as parasitic effects.
Since it is sometimes not possible to provide all data in the data sheet, the engineer may have to utilize measured spectra to choose the suitable component for the circuit design. To provide the best possible database, Würth Elektronik eiSos has implemented the online tool REDEXPERT, where spectra and other measurements are provided. 
In this note, we will recap the properties of such spectra and discuss how basic electrical characteristics can be inferred from it.