Chapter 7

Complex Numbers

John Bird

7.1 Introduction

A complex number is of the form (a+jb) where a is a real number and jb is an imaginary number. Therefore, (1+j2) and (5 –j7) are examples of complex numbers.

By definition, image and j2=–1

(Note: In electrical engineering, the letter j is used to represent image instead of the letter i, as commonly used in pure mathematics, because i is reserved for current.)

Complex numbers are widely used in the analysis of series, parallel and series-parallel electrical networks supplied by alternating voltages, in deriving ...

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