What is electrical noise, and what is its source?

Question

Quizplus · Accepted Answer

The Answer is "Electrical noise," as referred to when discussing electronic equipment, is any extraneous signal that tends to interfere with the signal normally present in or passing through a system. Induced noise might be EMI (electromagnetic interference)or RFI (radio frequency interference). It might be heard as a hum, buzzing, whining, or static. The cause might be traced to such things as an electric motor, ignition on a furnace, fluorescent and other types of electronic discharge luminaires, nearness to a power line, arc welders, power-supply switching circuits, cellular phones, other audio/video equipment, office electronic equipment, and nearness of computer cables to electric light and power wiring. These things are capable of creating unwanted waveforms that can scramble or distort digital signals.

What Is Electrical Noise, and What Is Its Source