Abstract

This paper discusses an analytical framework to model one-and two-ports in a way which avoids prioritizing either the voltage or the current as model variables. This approach allows for a truly general symbolic treatment of such circuits, avoiding the need to perform repetitive analyses in different working scenarios, and also displays a number of benefits from a theoretical point of view. The key ingredient is a homogeneous version of the Thévenin-Norton theorem for one-ports which possibly include controlled sources and coupling effects. This paves the way for the introduction of a comprehensive form for the transfer functions and the driving point immitances of two-ports, accounting for all possible impedance/admittance descriptions of the devices connected at the ports and also of the internal devices. Our framework allows e.g. for a universal definition of reciprocity but also for a straightforward derivation of Middlebrook's formulae in the context of the extra element theorem. Several examples illustrate the results.