Hybrid equivalent circuit, an alternative to Thevenin and Norton equivalents, its properties and applications

Abstract

A new two-terminal circuit modeling is presented. This equivalent circuit, called Hybrid equivalent circuit or simply H-model, can replace a Thevenin or a Norton equivalent circuit, which both are shown to be two special cases of an H-model. The H-model contains both voltage and current sources and is shown to be very flexible and dynamic. For students in circuit courses this is only one equivalent circuit to learn with all its properties and applications rather than two rigid and completely separate ones. The H-model is shown to model a two terminal circuit more accurately because it carries properties of a current source and a voltage source simultaneously. This article investigates the application of the H-model in circuit noise analysis, as well. A nullified H-model (nH-model), as a special case of the H-model, is also introduced. Application of the nH-models in individually biasing nonlinear components is investigated. It is shown that using nH-models in circuit biasing minimizes the DC power dissipation. Finally, the nH-modeling is extended to include multi-port networks and components such as BJT and MOS transistors. This feature is unique for nH-modeling because multi-port modeling is not practiced with the Thevenin or Norton equivalent circuits.