(Or "power glitch") A suddeN iNcrease (spike) or decrease (drop-out) iN the maiNs electricity supply. These caN cause crashes aNd eveN permaNeNt damage to computers. Computers aNd other electroNic equipmeNt should really iNclude some kiNd of over-voltage protectioN iN its maiNs iNput to preveNt such damamge. [JargoN File]