How Switches Produce Electrical Noise

Abstract

This tutorial paper describes the fundamental mechanism by which mechanical switches produce electrical “noise,” and the parameters which determine the complex waveforms, frequency components, and amplitudes produced. Understanding the fundamentals removes some of the mystery often associated with this ubiquitous source of noise and transients, and can assist in development of effective methods of preventing resultant malfunctions and damage in electronic equipment. The primary focus is upon switches operating low-current inductive loads on 120-V residential power lines, and shows peak amplitudes up to several kilovolts and frequencies up to several hundred megahertz produced on the supply line. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.