ZAP! The Shocking Truth About ESD

Category: Hardware

In the past I have warned readers to beware of static electricity (electrostatic discharge or ESD, in geek speak) on their gadgets and computers. Today, I’m going to explain in some detail what ESD is, what it can do to electronic devices, and how protect against this common hazard. Read on...!

What is Electrostatic Discharge?

I must confess that one of my favorite childhood pranks was shuffling around on a shag rug, and then touching my finger to a friend's earlobe. That's the low-tech definition of ESD. And maybe that's why I had to eventually make friends with computers (and apologize to my sister). But I digress...

ESD is a high voltage, low amperage electrical current that flows suddenly and briefly between two objects when they make contact or come very close to each other. Voltage is the difference in electrical charge between two points. Amperage is the rate of flow of an electrical current. So an ESD involves a transfer of electrical charge from an object that has a lot of it to one that has much less, but at a relatively slow rate and for a very brief period.

Electrostatic Discharge

The upshot of an ESD is that its high voltage is literally shocking, but its brevity and low amperage transfer too little electrical energy to seriously harm a human being. But it can produce hilarious YouTube videos like this one .

However, electronic components are much smaller and more sensitive to ESD than humans. Tiny transistors, resistors, capacitors, etc., are designed for very precise voltages and amperages. Zap them with an ESD that is wildly outside of their operating parameters and visible holes will be burned in them. Lightning is a very large ESD, and a lightning bolt can start a forest fire.

ESD starts with a buildup of electrons on an object, creating a large voltage (difference in charges) between it and other objects. Typically, rubbing two different materials together will transfer some electrons to one of them. Some materials acquire electrons more easily than others. (Sneakers on a shag rug, for example.)

Are You High Voltage?

Studies have found that a typically clothed human body can build up charges (called “electrostatic potential”) of between 500 and 2,500 volts during a workday - far more than the mere 25 volts it takes to damage electronic components, yet below humans’ perception level. Many plastics, especially Styrofoam, have even higher electrostatic potential. It is recommended to keep disposable coffee cups and other plastic items at least four inches away from electronic devices.

Even rubbing air molecules together rapidly builds up electrostatic potential, which is why blowing or vacuuming dirt out of a keyboard or computer can be hazardous. If you use “canned air,” use a brand made of “anti-static” gases that do not acquire electrons easily.

There is no way to prevent buildups of electrostatic potentials in all the objects, especially people, that come into contact with electronic devices. But we can make the ESD take a path that avoids the sensitive components inside.

People can ground themselves to avoid zapping their electronic devices. Electronics assembly, testing, and repair workers often wear wristbands that keep them constantly grounded via a wire attached to a nearby electron sink. Anti-static floor mats beneath one’s chair come with grounding wires that are attached to electron sinks; they’re a good idea, too.

Touching an "electron sink" before touching an electronic device will discharge your electrostatic potential; it’s a good thing to do each time you sit down at the computer. In practical terms, tapping an object that has a metal chassis and is plugged into a properly grounded outlet should do the trick.

Do Try THIS at Home

Mobile devices that people carry on their persons will gradually acquire the same electrostatic potential that their owners have. An ESD happens only when there is a difference in potentials between objects, as our hapless friend in the video above demonstrates. So you need not worry about the phone in your pocket or the laptop in your shoulder bag.

As mentioned above, the electrostatic potential of the human body is normally imperceptible, even when it discharges. Just because you don’t feel “static shocks” or see little blue sparks is no assurance that you aren’t jolting your computer with enough ESD to damage it. So take precautions even if you don’t see or feel any ESD.

Your thoughts on this topic are welcome. Post your comment or question below...

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Most recent comments on "ZAP! The Shocking Truth About ESD"

Posted by:

09 Aug 2019

agree all static is bad you never know when you touch something the static can damage it never know when it will fail

Posted by:

Lindsay Pinkham
09 Aug 2019

Your opening paragraph brought back memories of my brother torturing me in the exact same way! Shuffling on the carpet, then touching my ear.

Posted by:

09 Aug 2019

1) GREAT video!!! Reminds me of repairing old TV's and Radios - ALWAYS GROUND POWER TUBES!!! before you take the caps off. AND start by grounding the Chassis to discharge the high voltage capacitors!!! It only takes once for a person to learn. Well, after the video, I'd have to say MOST people.

2) I once had a small computer lab of about 60 computers. It sat at the VERY edge of the Northern Great Basins and Ranges where it got VERY dry in the winter - and getting a drink of water was always a shocking experience.

We used to have an "Electron Sink" that was just a grounded iron pipe at the door and EVERYONE, student or not, who came in HAD to ground themselves before they sat down. Over the years it slowly went away. We always got new computers that needed so much less work, that even I stopped wearing the grounded wrist strap after awhile.

I haven't thought about electrostatic discharge in FOREVER! -- I don't know why, but somehow I must have figured that computers had greater shielding (eg: a mini Faraday cage-esque)design than the older ones. AND, it's rare that I ever have to do ANY work inside my computer - in fact I can't remember the last time I messed with any kind of board or plug - everything seems MUCH better built than those old 8088 IBM's (the so-called "5150 model" - in California 5150 is the civil code section for "a danger to ones self or others") we started with. And,yes those 8088's COULD WELL BE a danger to themselves and others.

I haven't thought about electrical discharge in - probably more than a decade. THANK YOU for reminding me that it's still a real issue. I sure SHOULD have known it was still an issue around any kind of electronics - I think I must have just gotten lazy. So THANK YOU again - some times I just make up reasons that sound good to not do something, and even if the idea is as wacko as tiny Faraday cages - I sure convinced myself to not worry about zapping boards - or getting zapped BY components! I know that when someone brings by an old tube radio I still ALWAYS ground out the power tubes and chassis before I do anything else.

But those were vicious attacks by the tubes and capacitors - not me attacking them. I've been shocked by tubes and capacitors that have been unplugged for as long as five or six years. Somehow I thought "MODERN" (a concept that NEVER gets old) computers were somehow built and shielded -- not 'hardened' but at least 'firm'.

It's good to get a good old dope slap every now and then - thanks again Bob!

Posted by:

09 Aug 2019

I've fried a couple of laptops so far with static. I work in a hot/cold environment. So they gave me a cloth covered chair, to keep from sweating or freezing as the case may be. Well, every time i sit down, then get back up, I'm charged. So I've grounded my metal desk and so far that is working. But it is about time for a new laptop, so thanks for the information. ZAP.

Posted by:

09 Aug 2019

Great zap video! Reminded me of me when I was a HAM radio operator building Heathkit goodies.

Posted by:

09 Aug 2019

Dear Bob,
Thanks for informing me on a subject that I knew nothing about until I read your article. I will be more careful about ESD from now on.

Posted by:

Daniel Mielke
10 Aug 2019

Bob one thing I have learned about ESD is just because no damaged is noted at first doesn't mean it has sent happened sometimes it is just weakened only to die in the future.

Posted by:

bob a4
10 Aug 2019

I worked for a defense contractor testing and troubleshooting circuit cards, and anti-static precautions are very thorough and strictly enforced. The worst thing is that a component might be damaged but still work fine for now and get out to the field. If that component gives out then, lives are at stake.

Posted by:

10 Aug 2019

Great article, Bob!!!

So many computer users haven't a clue about ESD. Most of them do not repair their own computers, these days. Many times the computer is a Laptop that was given to them by the company they work for. So, when something goes wrong ... First call is to the IT Department.

For those of us, who are geeks or adventurers, we have had to learn the hard way about ESD. It usually takes only one good zap to make you realize that there is static in the air where ever you go. The need to ground yourself is important. Otherwise, it is so easy to completely destroy a good working computer.

I will agree that the newer components seem to be less prone to ESD, but ESD is still with us. I am not sure if this is due to newer materials when making motherboards, components and the grounding with resistance material, to ESD or not. I just know that I am not "messing" with my computer like I use to 20+ years ago.

All of us who use computers every day and for our work need to be reminded of the "dangers" of doing things that are not safe ... ESD or not knowing what your particular computer needs in the way of upgrading or simply cleaning out the dust that accumulates inside your desktop computer. Electricity attracts dust, look what happens to your ceiling fans ... Dust. It is the same with all the fans in your desktop computer.

Posted by:

12 Aug 2019

Any day one can play 'zap the cat' is not a fun day for computers.

Posted by:

Ken Splane
15 Aug 2019

Hi Bob,
Great article, and it reminds me of the time a number of years ago when I had a computer desk with the desktop on a lower shelf about six inches off the floor. We had two young brother cats, and they would be chasing each other and go under the computer shelf and the computer would actually shut off from the static generated. Once I figured that out, I got a different desk.

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