How to help your PC make it through the long, hot summer Lightning, blackout, brownout heat hurt them.

Personal computers

July 08, 1991|By Michael J. Himowitz | Michael J. Himowitz,Evening Sun Staff

When the summer air gets still and humid, and the lightning starts to flash on the horizon, it's time to think about your personal computer -- and whether you've protected it against the hazards that lurk in this most dangerous time of year for all things electronic.

Actually, if you wait until the lightning flashes, it may be too late. Even without lightning, summertime would be bad for computers. Brownouts, blackouts and just plain heat can wreak havoc on your PC. But with the right precautions -- some of which are simple and some of which aren't -- you can minimize the danger.

The problem with summer is that the weather can interfere with your computer's lifeblood -- a steady supply of clean electric current.

Computers are delicate instruments. The chips inside them are very sensitive to static electricity, and the circuitry itself is designed for low voltages.

When you plug in your computer and turn it on, a transformer inside the computer, known as the power supply, takes the 117 volt alternating current from your wall outlet and turns it into the more gentle 5 or 12-volt direct current your computer was designed for.

While most power supplies can handle normal fluctuations in wall current, summertime produces some abnormal conditions.

The biggest abnormal condition of them all is lightning -- the Attila the Hun of static electricity discharges.

Lightning is not a major problem in most office

buildings, which are properly grounded. But it can be a hazard in the home. You probably know at least one person who's told a tale of television sets exploding when lightning struck the TV antenna, even when the TV was turned off.

Many people believe the surge suppressors available in hardware stores and computer outlets will protect PCs from lightning strikes. They won't. In fact, nothing that relies on one electrical contact sitting a few millimeters away from another can keep lightning from bridging the gap.

The only sure way to keep a lightning strike from frying your computer is to pull the plug. During the summer, I've made a habit of unplugging my computer equipment whenever I'm away from the house. You should, too.

Likewise, if you're using a computer at home when a thunderstorm approaches, turn it off and unplug your equipment until the storm passes. Thunderstorms are very localized. You'll rarely have to interrupt your work for more than half an hour.

While lightning is an obvious hazard, brownouts and sudden blackouts aren't. You never know when they're going to happen.

In the hottest weather, when demand for power is at its peak, electric companies may reduce voltage to a

point at which your computer's circuitry can no longer compensate. This is known as a brownout.

A lightning strike miles from your home or office can cut power to your neighborhood completely. This is known as a blackout.

In recent years, the Baltimore Gas & Electric Co. has resorted to something it euphemistically calls "load shedding." When the demand for electricity is greater than the supply, the company just turns off the power to different sections of the city on a rotating basis. This is a man-made blackout.

Brownouts and blackouts pose a variety of problems for computer users. When the voltage gets too low, it can damage your PCs circuitry, and your computer may stop working altogether. Likewise, when the power returns to normal levels, it may do so with a vengeance, producing a momentary surge or spike that can damage or destroy delicate components.

While the sudden loss of power in a blackout won't necessarily hurt the computer's circuitry, it can ruin your day if your computer was writing data to the disk drive. Your data files may be corrupted, or your entire hard disk may be trashed. So back up your important files regularly.

If you're using your PC when the power goes out, turn everything off immediately and wait for the power to be restored before you turn on the computer again. That way you'll avoid damage from high voltage spikes that can accompany the return of electric current.

Good surge suppressors, which are primarily designed to deal with the everyday surges and spikes in of

fice building electric circuits, can protect your computer against this kind of voltage fluctuation. So it's a good idea to buy one, because you may not be around when the power goes out.

If you absolutely have to keep your PC running, or you want protection against hard disk crashes caused by sudden power loss, you may want to invest in an Uninterruptible Power Supply (UPS).

A UPS is basically a box containing a rechargeable battery and other circuitry that sits between your wall outlet and the computer.

Most UPS boxes contain filters, a voltage regulator, surge and spike suppressors that can deal with any power fluctuation short of a lightning strike. But their main advantage is that they sense a sudden drop in current in a few microseconds and automatically switch your PC to battery power.

A UPS isn't cheap, but it's a lot cheaper than losing the records of your accounts payable through a disk crash caused by a blackout.

UPS's start at about $300 and head toward the stratosphere. More money generally buys a UPS with more battery life, which means you can plug more than one computer or peripheral into it, or use it to run a single computer longer.

At the very least, a UPS will give you the opportunity to shut down your system in an orderly fashion. If your office has a computer network that uses a central PC as a file server, the file server should be on a UPS even if the other computers aren't.

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