In all cases there has to be a source and a victim for a path to exist thereby permitting a radiated or conducted coupling. Electromagnetic Interference (EMI), results from the operation of electrical or electronic devices involving rapidly changing voltage or current levels, which cause the generation of electromagnetic energy at discrete frequencies and over frequency bands.Discounting natural sources such as atmospherics or lightning, conduction and radiation emitting sources include:Radar and communications transmitters¡¢Receiver local oscillators¡¢Computers and their peripherals¡¢Motors and switches¡¢Power lines¡¢Fluorescent lights¡¢Arc welders and many more...