Complex Number

Complex Numbers are numbers that can be written in the form of: $ A + Bj $

Below is a graph of the imaginary plane that will help visualize what this means.

ComplexNumber ECE301Fall2008mboutin.png

A represents the real part of the complex number.

B represents the imaginary part of the complex number.

Both A and B must be real numbers.

Fact: Complex numbers are ONLY EQUAL if and only if the real coefficients are equal. Ex.

            A + Bj = C + Dj   A = C  B = D 
                  5 + 3j =/= 5 + 2j

Polar Form

In Polar Form, we use radius and angle instead of the distances x and y. r is the distance from the origin. θ is the angle in degrees.

              r*cos(θ) + j*r*sin(θ)

or written exponentially

              r*e^(j*θ)

Converting to or from Polar Form. Just remember these 3 easy equations.

                    x = r*cos(θ)
                    y = r*sin(θ)
                    r = sqrt(x^2 + y^2)

(having trouble with LaTeX. Anyone is welcome to clean these up.)

Alumni Liaison

Questions/answers with a recent ECE grad

Ryne Rayburn