What is electromagnetic interference?

Electromagnetic interference refers to any type of disturbance that affects electrical circuits of electronic devices. Sources of interference can either be man-made or natural. Any object that carries rapidly changing electrical currents can serve as the source of EMI.

There are multiple ways in which EMI can reach an electronic device and cause interference. It can be radiated, which is normally the case when the source and the affected device are completely separated. Or, it can be conducted, which means that the source and the device are connected in some way, usually by means of a cable that conducts a signal that causes interference.