What is it?
Did you ever touch a metal object and get a pain like a pinprick? Ever take your clothes off and hear a crackling noise? Ever see sparks when taking your clothes off in the dark?
That would be electrostatic discharge.
As stuff moves in the vicinity of other stuff, an electrostatic charge (static electricity) builds up. It’s busting for somewhere to go, so it finds the shortest route it can to Earth. It’s miniature lightning! When clouds come in proximity with one another, they charge up. Occasionally, they discharge with a bang and a flash of light.
What does it do?<o:p></o:p>
If lightning hits you and discharges THROUGH you, it might seriously damage or kill you. Here’s the thing: electrostatic discharge can seriously damage or kill your electronics.
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Ever had a component inexplicably stop working? Permanently? I’ve heard many, many people saying that ESD damage to electronic components is a myth. “I’ve built loads of perfectly working computers and never bothered with any of that nonsense.” The answer is that you might not know. Sometimes ESD can cause “transient” damage. That’s where inside an IC, for example, part of a track may become literally blown away by the force of an ES discharge. The component may continue to operate indefinitely (transient damage) or it may fail instantaneously. Either way, there’s no doubt that ESD weakens components.<o:p>
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Your body has an electrostatic field around it. As such, you don’t even need to touch components to cause damage. In proximity to components, the charge in your body causes the components themselves to become charged. Then, when you set the component down or it gets moved close to an object with a suitably different charge, it may discharge through the object.
What can I do about it? Part I - Easy, cheap solutions.<o:p></o:p>
Some precautions are inexpensive. It makes me cringe to see folk storing their ICs in polystyrene blocks. Sure it keeps the legs nice and straight, but you wouldn’t believe the amount of charge they can hold! Get yourself some anti static foam. There’s no shortage on eBay.
Speaking of eBay, if you’re ever buying electronic components (including PC memory, hard disks, or whatever), don’t buy it if the guy selling it has carefully arranged it on his bed sheets or on his carpet to take a photo of it!! These materials are some of the greatest generators of electrostatic fields and they have a massive storage capacity!
If you ever order samples, they come packed in ESD bags and tubes. Keep them. That’s what they’re for. Store your stuff in the dissipative bags when you’re not using it. Don’t just chuck them in a plastic box. These bags are normally silver or pink.
In fact, never use insulating materials (unless they’re specially coated with a dissipative material). Insulators hold charge. Being insulators, they also contribute to potential difference.
Printouts and photocopies are a big source of static charge. Paper holds a charge and guess what laser printing and photocopying do to paper? They charge it - like mad.
Polyester clothing is a curse. Don’t wear cheap underwear of man made materials. I’m not kidding, either. Polyester is an insulator and causes electrostatic fields to build up like crazy.
Most folk know the “hold the board by the edges” rule and the “don’t touch the pins” rule. These are a good step towards ESD preventative measures, but the only real way to stop damage from ESD is to ensure that you and the components are all at the same potential.
What can I do about it? Part II - Better, more expensive solutions.<o:p></o:p>
I know folk who say “Just touch a metal pipe or a radiator and that’s you grounded.” It’s true that touching a grounded item will dissipate any static on you, but don’t forget that your component may have a charge. It needs to be grounded too, so you’re both at the same potential.
This means you need to ground everything.
Unfortunately, providing an anti static environment can be a costly business, but it doesn’t have to be. For around $30, you can potentially save yourself days and days of pain. Here’s a <st1:country-region w:st=“on”><st1:place w:st=“on”>UK</st1:place></st1:country-region> supplier of anti-static mats.<o:p> </o:p>If you Google it, I’m sure you will find a local stockist. You’ll also need a wristband to keep yourself at the same potential as your components. This is the wrist strap from the company above.
What can I do about it? Part III - Industrial, very expensive solutions.<o:p></o:p>
Once you have yourself and your work surface at the same potential, you might consider anti static tools. These are conductive and dissipative so there is no potential difference between you and your workpiece.
Most ESD workplaces will insist that you wear a dissipative overcoat. These are normally cotton and the material may have a wire mesh woven through it.
Some ESD areas have a grounded floor manufactured from a conductive material. You can wear a “heel grounder” which is a wire which runs from the outside heel of your shoe to the inside to that as you walk around, any static is being conducted away to ground.
Conclusion<o:p></o:p>
<o:p>I </o:p>often wonder how many of my “Blue Screens of Death” were caused by me delving into my computer with no ESD precautions. I imagine that some of my problems in the past were due to memory or other components, weakened by electrostatic discharge while being built. Guess how many inexplicable PC crashes I’ve had since I bought my ESD mat? None. How many PICs have ceased to function inexplicably? None.
It’s worth thinking about.
