An electromagnetic pulse, or EMP, is a burst of electromagnetic radiation that can be caused by a number of devices. The most common source of EMP is a nuclear explosion. However it can also be caused by a large rapidly discharging capacitor bank or an explosively pumped flux compression generator. The resulting electric and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges. It is these effects that make EMP an effective Resistance weapon against Skynet forces. The Resistance has used a variety of such weapons against the machines, including EMP grenades and a modified nuclear missile.