How Surge Protectors Work
http://static.howstuffworks.com/gif/...or-diagram.gif
Quote:
As soon as the extra current is diverted into the MOV and to ground, the voltage in the hot line returns to a normal level, so the MOV's resistance shoots up again. In this way, the MOV only diverts the surge current, while allowing the standard current to continue powering whatever machines are connected to the surge protector. Metaphorically speaking, the MOV acts as a pressure-sensitive valve that only opens when there is too much pressure.
http://static.howstuffworks.com/gif/...ector-open.jpg
Quote:
Some surge protectors have a line-conditioning system for filtering out "line noise," smaller fluctuations in electrical current. Basic surge protectors with line-conditioning use a fairly simple system. On its way to the power strip outlet, the hot wire passes through a toroidal choke coil. The choke is a just ring of magnetic material, wrapped with wire -- a basic electromagnet. The ups and downs of the passing current in the hot wire charge the electromagnet, causing it to emit electromagnetic forces that smooth out the small increases and decreases in current. This "conditioned" current is more stable, and so easier on your computer (or other electronic device).
Quote:
To protect your equipment from surges, you need individual surge protectors for each outlet. These power strips range a great deal in quality and capacity (as we'll see in the next section). There are three basic levels of power strip surge protectors:
Basic power strip - These are basic extension cord units with five or six outlets. Generally, these models provide only basic protection.
Better power strip - For $15 to $25 you can get a power strip surge protector with better ratings and extra features, such as a protection indicator light and individual switches for each outlet.
Surge station - These large surge protectors fit under your computer or on the floor. They offer superior voltage protection and advanced line conditioning. Most models also have an input for a phone line, to protect your modem from power surges, and may feature built-in circuit breakers. You can get one of these units for as little $30, or you can spend upward of $100 for a more advanced model.
Uninterruptable Power Supply (UPS) - Some units combine surge protection with a continuous UPS. The basic design of a continuous UPS is to convert AC power to DC power and store it on a battery. The UPS then converts the battery's DC power back to AC power and runs it to the AC outlets for your electronics. If the power goes out, your computer will continue to run, feeding off the stored battery power. This will give you a few minutes to save your work and shut down your computer. The conversion process also gets rid of most of the line noise coming from the AC outlet. These units tend to cost $150 or more