Basic concepts: Two-terminal linear elements with memory and first-order linear circuits

Abstract

In this chapter, we introduce two-terminal components with memory, whose descriptive equations involve the time derivative of one descriptive variable. This implies generally speaking, that the circuit is described by a system of algebraic differential equations. As a consequence, the generic circuit variable can no longer be expressed as an algebraic function of the inputs, but has its own dynamics, which will be analyzed for simple (first-order) circuits. The concept of circuit stability is introduced. Moreover, discontinuous functions are defined, in particular the so-called unit step and impulse functions, which are often used in circuit inputs.