A lightning surge protector is a device that attempts to regulate the voltage supplied to electronics, thereby preventing potentially damaging voltage spikes. While a lightning surge protector is frequently used to protect computers, DVD players, and other sophisticated electronics from power surges, it is a common misconception that a surge protector can regulate voltage from a direct or very close bolt of lightning. Lightning surge protectors are normally meant to save electronic equipment from small surges, such as lightning that hits buried cable within a short distance from the home or office. Some power strips, also known as extension leads and power boards, have surge protection built in. These devices normally have varying specifications and capabilities, and they are commonly regulated by the local government.
While many people are used to the common elongated rectangular shape of lightning surge protectors, there is significant variation among them. Some, especially those with only a single outlet such as a portable surge protector, look like a small brick nestled against the wall outlet. In addition, surge protectors designed to protect a whole home by connecting to the electrical panel may look like an inconspicuous small metal box. A lightning surge protector with a large uninterrupted power supply may look like a large box with a few power outlets. Other novel surge protectors may have a few short cords that are reminiscent of small extension cords protruding from a small box.
Typically, a surge protector is plugged into the wall, either directly or with an attached cable, and then a computer or other electronic device is plugged into it. A lightning surge protector often has multiple outlets to plug in additional devices; for example, someone might plug her computer tower, computer monitor, and printer into the same protector. This type of lightning surge protector usually has an off switch to simultaneously power down all devices connected to it.
One type of surge protection device, the uninterruptible power supply, also includes battery backup capabilities. Some sensitive equipment, such as computers, can be damaged by sudden power loss as well as power spikes. Uninterruptible power supplies allow devices to run on their backup battery during losses of power as well as power surges. Sometimes specialized computer software is integrated with the uninterruptible power supply’s hardware so that computers will automatically shut down when the battery backup is running low. There are many different types of uninterruptible power supplies, ranging from small consumer devices that have only a few minutes' worth of battery power to large industrial devices designed to run commercial data centers for extended periods of time.