Electronic Circuit Analysis and Design by Driving-Point Impedance Techniques

By using driving point impedance (DPI) techniques a systematic approach to the analysis of electronic circuits can be developed which helps the engineer gain insight into circuit action. The answers, representing the circuit\´s currents, voltages, gains, and driving-point impedances, are written down by inspection of the original circuit diagram without resorting to equivalent circuits of flow graphs. The resulting answers are in a most simple form which can be easily interpreted by inexperienced persons since the relative magnitude of each factor is known. Thus, the student rapidly obtains a "feel" for electronic circuits. The method can also be used to complement a computer-aided circuit design and analysis. A tutorial treatment of the fundamental methods is presented and two examples are given. The simple example, which is complex by ordinary standards, has five input signals and three active elements; yet the output signal voltage is written out by inspection with each step explained. The second example, a two-stage transistor feedback amplifier, is used to demonstrate how the fundamental concepts are applied to complex feedback circuits. The gain, input impedance, and output impedance of the feedback amplifier are found and approximations are used to compare the answers to ordinary solutions given for such amplifiers. The answers obtained by DPI analysis methods are also compared to equivalent answers found by node analysis.