Circuit Analysis For Dummies

Chapter 15

Phasing in Phasors for Wave Functions

In This Chapter

Describing circuit behavior with phasors

Mixing phasors with impedance and Ohm’s law

Applying phasor techniques to circuits

Phasors — not to be confused with the phasers from Star Trek — are rotating vectors you can use to describe the behavior of circuits that include capacitors and inductors. Phasors make the analysis of such circuits easier because instead of dealing with differential equations, you just have to work with complex numbers. I don’t know about you, but I’d take working with complex numbers to solve circuits any day over using differential equations.

Phasor analysis applies when your input is a sine wave (or sinusoidal signal). A phasor contains information about the amplitude and phase of the sinusoidal signal. Frequency isn’t part of phasor form because the frequency doesn’t change in a linear circuit.

This chapter introduces phasors and explains how they represent a circuit’s i-v characteristics. I then show you how phasors let you summarize the complex interactions among resistors, capacitors, and inductors as a tidy value called impedance. Finally, you see how phasors let you analyze circuits ...