Motivating Two-Port Network Analysis through Elementary and Advanced Examples

Abstract

We seek to motivate the use of two-port network circuit analysis techniques by proposing two examples: one is elementary, the other is advanced. In particular, we start by deriving the transmission matrices for small-signal equivalent models of the BJT and MOS transistors. We then proceed to the first example where we explain the function of a Gyrator in a very clear way aided by Spice simulations. In the second more advanced example, we show how to systematically analyse the classical Cascode amplifier in a general way that is independent of whether it is realized using a BJT or a MOS transistor. The two examples highlight the strength and generality of the not-so-popular two-port network analysis which is usually introduced to undergraduate students much later than other circuit analysis techniques. This delay results in a preference for using mesh and nodal techniques to model and analyse electronic circuits.