Karl W. SwartzComputer Notebook — Electrical Disturbances

Have you ever been taking a shower when someone flushes the toilet? This is what your computer experiences when the refrigerator or air conditioner comes on. Do you ever see the lights flicker of dim? They are experiencing the same thing. This is a severe drop in voltage due to a large appliance sucking up all the available electricity. If it is bad enough, your computer may restart itself, or lock up if an operation is in progress. Listen to your computer. Do you hear the fan speed up and slow down? This is the same thing going on. Your computer is experiencing fluctuating voltage (voltage is like the water pressure in your shower). It has built-in regulators that can compensate for some of this, but only so much. Then you begin to experience problems with your computer.

Have you ever been listening to the radio or watching TV (before cable) when an airplane or someone’s CB causes interference and static, and you can no longer hear your program? This is what your computer experiences when you run the vacuum cleaner or fan, or turn on a fluorescent light. This is called EMI (electro-magnetic interference) or RFI (radio-frequency interference), depending on the type and source. Again, your computer should filter out some of this, but it can do only so much. When this static gets through, it can mimic bits of data and can corrupt your files and programs, turning your data to garbage and causing your computer to crash.

How can you avoid these problems? First, you should never have your computer on the same circuit as a major appliance. Ultimately, all of your circuits join together at the main breaker box, but the farther removed your computer is from other appliances, the more diluted the effects. This is just the same difference between someone flushing the toilet in the same bathroom as your shower, or in the one downstairs. If it is far away, you may still notice it, but much less.

Second, your computer should be plugged in to a good surge protector. This acts as a filter for most of these disturbances, either blocking them at some level, or smoothing out the abruptness. A good surge protector should guard against voltage surges (hence the name), as well as EMI and RFI. Read the label before you buy, it will list the protection provided. Make sure you are not getting simply a multi-outlet strip, they are often indistinguishable in appearance. A multi-outlet strip will usually have a fuse or breaker, but this is simply to prevent the circuit from overloading. It is to protect your house from burning down, but provides absolutely no protection for your computer. Look for the phrases "surge protector" and "EMI and RFI filter".

Third, shut your computer down and unplug it completely during a thunderstorm. A lightning strike, even a long distance away, can induce a voltage surge that nothing can stop, and it can fry anything on the circuit. If you have a modem, disconnect the phone line. Lightening can travel through any conducting medium (wires) and destroy anything in its path.

Copyright © 2004 Karl W. Swartz — http://KarlSwartz.com
You may freely reproduce and share this text, only if it is not altered and includes this notice.