Surge protector, also called a surge suppressor, is a device that protects computers and other sensitive electronic equipment from damage that can be caused by excessive voltage or current in a power line. Such excessive voltage may occur as a spike or a surge. Each of these types of excessive voltage lasts only a fraction of a second, but a spike is briefer than a surge. Spikes and surges are most commonly caused when various components switch on and off in such high-powered electrical equipment as air conditioners and elevators. These actions require brief bursts of power. Such power requirements disrupt the steady voltage flow in an electrical system, resulting in spikes, surges, and short drops in voltage called sags. Much stronger surges can occur when lightning strikes near a power line.
A surge protector is plugged into an electrical outlet and has a number of outlets into which electronic equipment can be plugged. Components in the surge protector prevent surges from being passed on to the electronic equipment. Most surge protectors have metal oxide varistors, components that divert excessive voltage from large surges to an electrical ground (see Ground ). Most surge suppressors cannot protect equipment from the intense surges caused by lightning strikes, so computers and other sensitive electronic equipment should be unplugged during thunderstorms.
