Using circuit transformations for the evaluation of amplifier parameters

A technique for signal analysis of electronic circuits, using simple circuit transformations, is presented. The circuit transformations are based on the application of the Th´evenin’s and Norton’s theorems. The method is an alternative to directly solving the circuit equations, and is especially useful in some cases for the evaluation of gain and resistance seen from two nodes. A set of examples is presented. Though the procedure is a general method, it is better to regard it as an alternative technique, specially useful in several cases where it can help the student to grasp the operations and get insight into the role played by some configurations used in amplifier circuits.