The cognitive psychology accredits to the identification of frequently recurrent schemes, named elementary patterns, and their relationship a key role in the learning-understanding processes (Garner, Hawker Brownlow Education, 2008). The capability of spotting frequently occurring elementary circuits, referred in the follows as basic patterns, is therefore of paramount importance for reading and understanding electronic circuits. The knowledge of basic patterns and the ability of spotting them in a given electronic circuit makes possible to iteratively decompose it into a structured network of elementary circuits. The operation principle and the properties of the given electronic circuit can therefore be deduced from the properties of the basic patterns. In particular, if the basic patterns are equipped with mathematical expressions of their main properties as gains and input/output impedances, the decomposition into basic patterns leads to a calculation methodology that saves calculation time and reduces error probability. This chapter focuses first on the analysis of basic patterns, as common-emitter or common-drain amplifiers. The obtained results are then used to analyze fundamental patterns as cascode, current mirrors, and differential amplifiers. In particular, the aim is the calculation of the mathematical expressions of the small-signal current and/or voltage gains and input and output resistances in the mid-band, where the circuits are capacitorless.