|Practical Computer Advice
from Martin Kadansky
Volume 9 Issue 4
|ZAP! How to Deal with Static Electricity
To read this issue on my web site, please visit:
Has this ever happened to you? You walk across a rug, then touch a doorknob or light switch or computer or another person and ZAP! You feel a spark on your fingertip, anywhere from a mild flicker to a painful shock. Here is my advice on what you can do about this.
How a static charge accumulates
Static electricity can build up in your body when you come in contact with materials that transfer an electrical charge to you. If you're also insulated from any "conductive outlet" (not in contact with an electrical ground, e.g., wearing rubber-soled shoes), instead of draining away, the charge stays. Plastic and synthetic materials can cause this, as well as many organic materials, including hair and fur. For example:
Static build-up is most likely to occur when the humidity is low, for example during the winter when the air is dry and you may be indoors more than in the warmer weather. It will also depend on the clothes and shoes you're wearing, and also on your body chemistry (i.e., how much your body electrically acts like a capacitor).
- You walk across a rug.
- You pet your cat or dog.
- You slide across a car seat.
- You run your hands across a coat or jacket made of fleece or wool or fur.
In an informal and unscientific survey of friends and colleagues, I've also learned that:
can cause a build-up of static electricity, depending on the person and the circumstances.
- Wearing shoes with memory foam on the inside,
- Walking on a deck made from composite materials, or the rubberized floor in a dance studio,
- Having flannel sheets on your bed, and
- Walking on hardwood floors treated with polyurethane
This build-up and discharge of static electricity that you experience is a miniature version of the same mechanism that causes lightning and thunder.
The good news about modern computer equipment
The first computers I used in the 1970s took up most of a room and were housed in climate-controlled environments. I don't remember any concerns about static electricity, nor any damaging incidents.
However, when microcomputers became available for consumers to use in the 1980s, static electricity was a major concern. "Touch-me-first" pads that connected to a nearby ground (like a wall outlet or radiator) were common and important accessories. As you sat down to use your Atari or Apple II or the computer you built from a kit, you would touch that pad first to discharge any static charge you were carrying and avoid damaging your delicate (and expensive) equipment.
These days, the shielding and grounding of computers has improved to the point where the need for regular users to have "touch-me-first" pads has disappeared into history. When I walk across my rug and touch my laptop computer, I sometimes do feel a static shock, but my computer has never had a problem. However, technicians who take computers apart to fix or service them definitely need to be careful about static electricity.
How to reduce static electricity
You may still have good reasons to be concerned about static electricity. For example:
Here are a few ideas for reducing static electricity:
- You may feel that giving your computer static shocks is a bad idea, regardless of the improvements in computer design over the years.
- You may have other electronic devices that might not have good protection from static shocks, including printers, scanners, smartphones, tablets, televisions, stereo systems, cable boxes, Tivos and DVRs, etc.
- You may find that getting static shocks from touching doorknobs or light switches is painful or annoying, and that giving them to other people (or pets) gets you into trouble.
See "Where to go from here" for resources containing even more ideas.
- Increase the humidity with a humidifier or vaporizer or pan of water on a stove or radiator. Dry air is an insulator, making static electricity more likely. Humid air is a conductor, so it helps dissipate static.
- Dry skin carries more static electricity. Use hand lotion to moisturize your skin.
- The soles of your shoes may be insulators. Try shoes with different soles, or see whether going barefoot (if possible) makes a difference.
- Spray your carpet with an anti-static agent. Be sure to let it dry before walking around so you don't slip and fall. Or, try removing your carpet altogether.
Discharging your static electricity before it can damage your electronics
Completely eliminating static electricity from your environment might not be possible or practical. Here are some simple ways you can discharge your static build-up before you touch your valuable electronics:
Discharge your static electricity when getting out of your car, especially at a gas station
- Touch a metal object connected to an earth ground: A water faucet, water pipe, radiator, the grounded screws in a wall outlet or light switch plate, the metal frame of a lamp or appliance, etc.
- Touch any other large metal object: A file cabinet, doorknob, metal table or chair, etc. While probably not connected to an earth ground, it's very likely to have a different or neutral charge compared to you, and will take yours.
If you experience a static shock when getting out of your car, try this: After you've slid across the seat and opened the door, touch a metal part of the car's door or frame with your bare hand right before your feet touch the ground. You may not feel any spark, but doing this will probably dissipate your excess charge.
This is important to do at the gas station, especially if you pump your own gas, to avoid causing a spark near the pump and possibly igniting the gas fumes. Don't forget to discharge again if you get back in your car and get out a second time!
Also, if you are going to fill a gas can or portable fuel container, avoid building up a dangerous static charge by taking the container out of your car or truck and placing it on the ground, keeping the nozzle in contact with the container the entire time you're filling it, and putting the cap back on the container before moving away from it.
Reduce or eliminate the pain of that static electricity ZAP!
For some people, getting a static shock might be an amusing surprise, but for others it's quite a painful experience. If you can predict when a static shock is going to occur, here are some simple ways you can reduce or eliminate that pain:
Homemade grounding strip
- Instead of using your finger to touch, say, a doorknob, use a knuckle or elbow instead. They're not as sensitive as fingertips.
- Hold a small metal object in your hand, like a key or coin or thimble or screwdriver or ring. Make sure you're holding the metal part (not any plastic handle) and then touch the doorknob with that instead. The spark will occur at the tip of the metal object instead of on your skin. Don't use a valuable ring, it might tarnish from the spark, and don't use your cell phone.
At my desk I have found that touching my metal clamp-on swing-arm lamp is a convenient way to discharge my static electricity before touching my computers. However, when I want to watch the television shows I've recorded on my Tivo DVR, if I happen to touch the Tivo's case, in the winter I often feel a static shock. Some of the time the shock makes the Tivo stop working; luckily rebooting it has brought it back to life, but this motivated me to make my own simple "touch-me-first" pad that combines:
I put this grounded ruler on the table in front of my Tivo. Now that I always touch the ruler first to discharge any static I've built up, I haven't shocked my Tivo since!
- A "grounding cord": Its 3-prong end plugs into a grounded wall outlet, its 6-foot wire only connects to the ground prong, and the other end of the cord has a metal alligator clip.
- A metal ruler: I attached the grounding cord's alligator clip to one end.
Static electricity isn't all bad
A number of technologies that we take for granted depend on the use of static electricity, including photocopiers, laser printers, automotive paints, and certain types of air filters.
Exploit what you've learned here for dramatic effect
The next time you or your significant other wears a fleece jacket or wool coat, run your hand over the fabric and then kiss them. If you get a (presumably mild) shock, you can say, "See? We've still got sparks!"
Where to go from here
How to contact me:
phone: (617) 484-6657
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I love helping people learn how to use their computers better! Like a "computer driving instructor," I work 1-on-1 with small business owners and individuals to help them find a more productive and successful relationship with their computers and other high-tech gadgets.