# CHAPTER 2

*Circuit Elements*

**IN HIS CHAPTER**

**2.1** Introduction

**2.2** Engineering and Linear Models

**2.3** Active and Passive Circuit Elements

**2.4** Resistors

**2.5** Independent Sources

**2.6** Voltmeters and Ammeters

**2.7** Dependent Sources

**2.8** Transducers

**2.9** Switches

**2.10** How Can We Check …?

**2.11 DESIGN EXAMPLE**—Temperature Sensor

**2.12** Summary

Problems

Design Problems

## 2.1 *Introduction*

Not surprisingly, the behavior of an electric circuit depends on the behaviors of the individual circuit elements that comprise the circuit. Of course, different types of circuit elements behave differently. The equations that describe the behaviors of the various types of circuit elements are called the constitutive equations. Frequently, the constitutive equations describe a relationship between the current and voltage of the element. Ohm's law is a well-known example of a constitutive equation.

In this chapter, we will investigate the behavior of several common types of circuit element:

- Resistors.
- Independent voltage and current sources.
- Open circuits and short circuits.
- Voltmeters and ammeters.
- Dependent sources.
- Transducers.
- Switches.

**2.2 ***Engineering and Linear Models*

The art of engineering is to take a bright idea and, using money, materials, knowledgeable people, and a regard for the environment, produce something the buyer wants at an affordable price.

Engineers use *models* to represent the elements of an electric ...