ABSTRACT
To describe the effect of any element within an electronic circuit or of the connection of different circuits, the immittance is a characteristic quantity. It simply provides a relation of sinusoidal voltage and current at the terminals of the element as a function of frequency. The immittances of the fundamental passive circuit elements are derived from their instantaneous volt age current relations. The immittance of ideal inductors and capacitors is purely imaginary with different signs according to the phase shift of plus or minus 90 degrees between voltages and currents. Since immittances are complex quantities, one must determine two parameters: magnitude and phase or real and imaginary part, described as vector measurements. There exist different techniques depending on frequency range and required accuracy. Automated and precise immittance measurements over a wide frequency range are best carried out with a vector network analyzer.
