An electromagnetic pulse (also known as EMP) is a pulse of electromagnetic radiation emitted by certain devices that can render the technology of some races inert, albeit temporarily. On Earth, EMP was discovered by accident. Besides the Tau'ri, other races are known to have used EMP. All Ancient technology is apparently impervious to EMP. (SGA: "The Siege, Part 3")


An EMP above Atlantis


EMP was used a fair number of times over the years.