Linear Circuit Models Derived via Computer Optimization

To make more efficient use of the computer as an aid in obtaining linear small signal circuit models, a method of successive approximation is presented and used to obtain a variety of circuit models. Several useful search strategies are presented and specific examples illustrate their use in deriving better approximations from an initial starting point. The relative merits of various search strategies are compared to furnish guidelines for future use. The modeling techniques are also applied to specific resistor and transistor characterization problems. The hybrid-pi model for the transistor is developed in a way which allows considerable flexibility in the inclusion of parasitic effects. A final example models a practical amplifier at frequencies up to UHF.