In mathematics and engineering, the complex operator refers to a mathematical operator or function that is applied to complex numbers. Complex numbers consist of a real part and an imaginary part, usually denoted as a+bi, where a is the real part, b is the imaginary part, and i is the imaginary unit (i).

The Imaginary Part is used often used in Engineering, especially in areas that are concerned with AC circuitry.

The imaginary unit j is defined such that =−1. It is used to represent the imaginary part of a complex number in the context of electrical engineering calculations. For example, a complex number a+jb represents a combination of a real part a and an imaginary part b multiplied by j.

Using j instead of i helps to avoid confusion in electrical engineering calculations, where i commonly represents electric current. This convention is particularly prevalent in the analysis of AC circuits, where complex numbers are used to represent voltages, currents, and impedance.

For instance, in the analysis of an AC circuit, the impedance of a resistor R can be represented as R, while the impedance of a capacitor C is represented as 1jωC​, and the impedance of an inductor L is represented as jωL, where ω is the angular frequency of the AC signal.

Other common complex operators include:

Complex Conjugate: The complex conjugate of a complex number a+bi is a−bi. It is obtained by changing the sign of the imaginary part.

Real Part: The real part of a complex number a+bi is a. It represents the projection of the complex number onto the real axis.

Imaginary Part: The imaginary part of a complex number a+bi is b. It represents the projection of the complex number onto the imaginary axis.

Magnitude or Absolute Value: The magnitude (or absolute value) of a complex number a+bi is . It represents the distance of the complex number from the origin in the complex plane.

Argument or Phase: The argument (or phase) of a complex number a+bi is the angle formed by the vector representing the complex number with the positive real axis. It is usually denoted as θ and can be calculated using trigonometric functions.

Complex Exponential: The complex exponential function eixeix, where xx is a real number, represents rotation in the complex plane and is related to trigonometric functions through Euler’s formula:

Back to Glossary Index Page