Harmonics arise naturally in physical systems, acoustic instruments, and electrical networks due to inherent nonlinearities and periodic oscillations. In music, striking a string creates standing waves that produce integer-multiple overtones, giving instruments their rich unique timbre. In electrical engineering, harmonics occur because modern power loads—such as computers, LED drivers, variable frequency drives, and switching power supplies—draw current in non-sinusoidal, abrupt pulses rather than smooth waves. These nonlinear devices rapidly switch semiconductor components on and off, distorting the standard AC sine wave and generating multiple higher-frequency harmonic currents that circulate through the electrical grid.