We no longer live in a world of an incandescent bulbs. The digital revolution introduced us to many more electronics, including LEDs, VFDs, PLCs, electric vehicles, and other computerized loads, aka nonlinear loads. Nonlinear loads, the modern equipment is digital, programmable, and automated. The nonlinear loads are fast, efficient, and smart.

The operating principle of the nonlinear load is to “switch” AC to DC, DC to AC frequently. The switching process generates “switching noise” – an unwanted electrical signal in the system. The switching noise is also called higher-order harmonics (3-100kHz) or high-frequency noise.

Each nonlinear load uses hundreds of switching components such as MOSFETs, IGBTs, ICs in its circuit. The components use switching frequency from 25-300kHz with their harmonics noise in 1MHz. 

The following two graphs show the difference between a linear and a nonlinear load. The first picture shows a clean sinusoidal waveform from the liner load, while the second picture shows the distorted waveform with the noise on the peaks and zero-crossing. 


Linear load waveform

Noise free waveform from the linear load

Distorted waveform from the nonlinear load

Switching noise is the higher-order harmonics noise that may not be filtered out using traditional harmonics filters. Custom-designed low pass filters tuned at the high-frequency noise are the only solution to remove and protect your facility from the higher-order harmonics.