Circuit Simulation with SPICE OPUS pp 1-35 | Cite as

# Introduction to circuit simulation

## Abstract

This chapter introduces the reader to the basic notions in the field of circuit simulation. It is highly recommended that you read this chapter before reading any other part of the book simply to become familiar with the terminology used in the chapters that follow.

We will start with an introduction to circuit operating point calculation. Then we will continue with operating point sweeps and definitions of differential gain, resistance, and conductance. Next we move on to time-domain modeling and analysis.

A large part of this chapter is dedicated to the frequency-domain analysis of circuits with small signal excitations. We will give a brief introduction to Fourier transformation and small signal circuit modeling followed by a short tutorial on small signal noise modeling and analysis. At the end of the chapter, we move to the Laplace transformation, *s*-domain modeling, and pole-zero analysis.

The order in which analyses are described in this chapter is somewhat different than in subsequent chapters. We have done this because the basic principles of the Fourier and Laplace transformations are harder to understand than circuit analysis in the time domain. On the other hand, the implementation of the two transforms is much more related to operating point analysis than it is to time-domain analysis.

Be aware that *Y* in this chapter denotes the Fourier transform of the circuit solution vector. In all the remaining chapters, *Y* denotes the complex admittance, as used everywhere else in the literature on circuit theory.