What are the main sources of EMC problems?

In all cases there has to be a source and a victim for a path to exist thereby permitting a radiated or conducted coupling. RF Interface (sometimes referred to as RFI), more correctly known as Electromagnetic interface (EMI), results from the operation of electrical or electronic devices involving rapidly changing voltage or current levels and which cause the generation of electromagnetic energy at discrete frequencies and over frequency bands.

Discounting natural sources such as atmospherics or lighting, conduction and radiation emitting sources include;

• Radar and communications transmitters
• Receiver local oscillators
• Computer and their peripherals
• Motors and switches
• Power lines
• Fluorescent lights
• Arc welders
• and many more…