In the investigation of a feedback amplifier, the two-port network method (supra Sect. 6.6 ) offers, over the nodal analysis and the return ratio method (supra Sect. 6.7 ), the advantage of shorter mathematics but at the price of two conditions: the identification of the feedback type and the possibility of describing the amplifier in the loop and the feedback network as two-port networks. The former condition is a drawback because the identification of the feedback type in a real circuit is a not trivial task; it is largely based on the experience, for no well-defined rules are available. The latter condition is a limitation because in a real circuit it is not always possible to describe the amplifier and the feedback network as two-port networks. This chapter reports the analysis of several examples of feedback amplifiers with the double goal in mind of gaining skill in the identification of the feedback type and of pointing out the limitation of the two-port network method. To this aim, each example of feedback amplifier is investigated by means of the nodal analysis and of the two-port network method, as well.