In mathematics, a Fourier
series decomposes a periodic function or periodic signal into a sum of simple oscillating functions, namely sines
and cosines (or complex exponentials). The study of Fourier series is a branch of Fourier analysis. Fourier series
were introduced by Joseph Fourier (1768–1830) for the purpose of solving the heat equation in a metal plate. It
led to a revolution in mathematics, forcing mathematicians to reexamine the foundations of mathematics and leading
to many modern theories such as Lebesgue integration.
 WikipediaHere are the Fourier Series for a few of the simplest and most common waveforms.
(See general formula for
Fourier Series)

Triangular Wave 

Square Wave 

Halfwave Rectified Sine Wave 

Fullwave Rectified Sine Wave 
