The most serious threat to your computer and other electronics today might not be a virus or spyware attack. It's a summer thunderstorm - or more precisely, the sudden blackouts and power surges that lightning can cause.
If you haven't done anything to protect your equipment against this threat, it's time. And if you haven't checked the protective devices you bought a couple of years ago, it's time for that, too.
Here's why: Most of the components in your PC are designed to operate at 12 volts, 5 volts or even lower levels. Your computer's power supply (which sits just inside the case where the fan on the back can cool it) normally transforms the sizzling, 120-volt AC current in your house into the low-voltage, direct current that your PC needs.
The power supply can take care of small, normal fluctuations in line voltage. The problem is a sudden spike that can fry the insides of your machine. This is most likely to happen when the voltage returns after a power disruption - and it may happen repeatedly if the electricity comes back, goes out, and comes back again.
But surges can also happen in a home when a refrigerator, air conditioner or some other appliance on the same circuit cycles on. Surges are endemic in some office buildings.
The first line of protection for your PC (or high-definition television, or any expensive electronic gadget) is the surge suppressor. Usually sold in power strips with four or more outlets, these devices divert surges to the ground wire of your home or office. Better units also filter and condition the power to protect your equipment from smaller glitches and burps that can damage it over time.
You can buy a surge suppressor for as little as $8 or spend $75 and up, depending on bells and whistles. The first thing to look for is an Underwriter's Laboratories label certifying the device as a Transient Voltage Surge Suppressor compliant with UL Standard 1449.
Now consider three specifications, all of which should be detailed on the box or label. One is the amount of energy the suppressor can absorb, measured in joules. Look for a minimum of 700 joules. More is better. The next is the clamping voltage - the voltage at which the suppressor starts to do its job. Lower is better. Most experts recommend a maximum of 400 volts. Finally, look for the response time. Again, lower is better - preferably under 10 nanoseconds.
There are also two must-have indicator lights. One shows whether the strip is turned on (it's all too easy to kick the switch into the off position). The other shows whether you're still protected against surges. Every time it absorbs a surge, your strip dies a little - eventually it offers no protection at all. A glowing indicator lamp tells you the suppressor can still do its job. If you have an older suppressor, check it out. Even then, it's not a bad idea to replace suppressors every couple of years.
Other useful features include outlets arranged facing outward, rather than in line, and spaced wide enough to accommodate the ubiquitous little black boxes that charge cell phones and other gadgets. Some strips also offer protected jacks and connectors for telephone and cable lines.
If you have lots of gadgets and don't want to worry about protecting each one, consider a whole-house surge suppressor. These devices cost $150 to $250 and must be installed by an electrician at your breaker box, which may double the cost of the unit itself. But once you have one, it will protect all the equipment in your house from outside surges. BGE Home, the utility company's eponymous consumer services spinoff, has one called SurgeGuard that it will install and lease for a monthly fee.
Surge suppression is the first half of protecting your valuable equipment. For some devices, especially a PC, you may also want an uninterruptible power supply, or UPS. A UPS is a heavy, bulky box containing a rechargeable battery that sits between the wall outlet and your computer and other components. Most have outlets for several devices.
When the voltage drops precipitously, the battery power kicks in and keeps your PC and other devices running from 10 minutes to an hour, depending on how equipment you plug in and much you're willing to pay.
This protection is especially important for PCs, because a sudden power loss while the computer is writing data to the hard drive can seriously scramble the disk and even render it unusable - along with all your data, music, videos, financial records and so forth. A UPS also will give your equipment a smooth, untroubled ride with a minimum number of restarts in areas where there are frequent, short blackouts.
Most consumer and small business UPS units also provide surge suppression and power line filtering. They typically have a couple of outlets with battery backup and several more with surge suppression but no auxiliary power.
Generally speaking, you should use battery backup only for your critical equipment to maximize battery life - never plug in printers or scanners. I plug in only my PC, cable modem and router. I wait until I'm ready to shut down the system before plugging in the monitor, so I can see what i'm doing
The backup capacity of UPS units is measured in Volt/Amps (VA). Determining how much UPS you need can involve some onerous calculations, so your best bet is one of the handy calculators on a UPS manufacturer's site. It will probably overstate your needs, but it's better to buy a bit more juice than you need than too little.
The calculator on the American Power Conversion Web site (aps.com) recommended a unit of at least 800 VA to provide 10 minutes of backup power to my desktop system (computer, monitor, router and cable modem). They start at $150. Other experts say I could get away with a somewhat lighter-duty model, in the 600 to 700 VA range, for $100 or so.
There's no need to plug a laptop computer into a line with a battery backup - the laptop's battery kicks in automatically when the power goes out. However, it's always a good idea to plug it into a surge-protected outlet.
A final word: If you're working at home and hear a nasty thunderstorm approaching, give your PC the best protection available: Shut it down, unplug it and put your feet up untll the storm passes. It rarely takes more than a half-hour, and it's guaranteed to work.