摘要：Abstract: Generally, there are two reasons for using the symbolic analysis method: to accelerate and improve the accuracy of numerical computations, and to facilitate understanding the dependency of a transfer function vs. some physical parameters. Exact formula tends to be very large and out of the human perception. Thus, in the second approach one expects rather simplified results, but close to the exact one. One of the methods of simplification can be modeling of active devices with some pathological components like nullators, norators, and current and voltage mirrors. In recent years, there were several papers published on this subject. Unfortunately, some of published models are wrong. Seemingly, they work in the proper way, but in practice they model a little bit different device, sometimes non-existing one. Additionally, a few models cannot work at all, because they always yield the singularity. Even disregarding the wrong models, the others still contain auxiliary unit resistors that cause models redundant and not effective enough. They can yield cancelations. The paper presents a formalized method of creating of alternative models, which are free off the drawbacks listed above.
