Chapter 9 - Circuit Elements and Circuit Variables

Abstract

This chapter highlights circuit elements and circuit variables. Systems containing analog elements are called circuits, networks, or analog systems. Analyzing a circuit usually means finding the mathematical representation of one or more signals in the circuit or finding the transfer function. Once the transfer function is determined, the circuit can be viewed using a tool in either the time or frequency domain. Analysis of an electric circuit or analog model generally calls for the solution of one or more differential equations. Even the solution of a simple circuit defined by a first-order differential equation can become tedious if the signals are complicated. In both, electric circuits and mechanical systems, only two variables are needed to describe a system's behavior. An element, be it electrical or mechanical, can be viewed as simply the defining relationship between these two variables. While these variables are different for electrical and mechanical systems, they have much in common. The basic concepts related to circuits and analog systems, electrical and mechanical variables, and electrical elements are elaborated. It provides details about phasor representations and zero initial conditions. Concepts related to passive mechanical elements, elasticity and, mechanical sources are also discussed.