The primary root cause of electrical harmonics in modern power systems is the widespread utilization of non-linear loads. Unlike linear loads—such as simple resistive heaters or incandescent lamps, which draw current smoothly in direct proportion to applied voltage—non-linear loads draw current in abrupt, short pulses or non-sinusoidal waveforms. Common examples of non-linear equipment include variable frequency drives, switching power supplies, computers, LED lighting ballasts, rectifiers, and uninterruptible power systems. These devices rapidly switch semiconductor components on and off, distorting the standard AC sine wave and generating multiple higher-frequency harmonic currents that circulate back into the electrical distribution grid.