My first year in the real world entailed specializing in Electrostatic Discharge (ESD) management and one of the activities I enjoyed was giving training sessions to new employees. In the electronics industry, ESD has been seen as a threat to profitability and customer satisfaction because of the sheer number of products falling out on a typical manufacturing day just by a single spark straying from an operator's fingers. And if some of these units pass quality assurance and make their way to the market, we get irate phone calls from customers receiving these "walking wounded" electronic parts.

It's not an exciting field though, for the idealistic me at that time, since all I need to do was to check for compliance in the manufacturing floor for ESD countermeasures day in and out. No white papers were asked, which the writer in me sulkingly obliged and subtly resisted. And so in the next few years I moved into "hard" operations engineering and lately, research and development. I thought that the training material I made when I recently opened it got corrupted, was the end of my fleeting relationship with ESD. Dean's entry on this irritant however, and the existence of all-too-technical information on ESD wanted me to write this special Skythologies entry on static electricity and electrostatic discharge.

To office cube dwellers, static electricity means being "zapped" while reaching for the doorknob in a drab-gray carpeted room. Too aware perhaps, that they know it's not a stern reminder to get back to their seats, start working and keep coffee breaks and water dispenser conversations at a minimum. Partially, they are correct, but the term "static electricity" is a misnomer. In basic electricity, surfaces can have positive or negative charges (much like the positive and negative poles seen in batteries). These surface charges are what constitutes static electricity, officially defined by the ESDA as "an imbalance of electrons on the surface of a material". And they are an accident waiting to happen.

One fundamental law of nature, which is also applicable to humankind, is that it prefers the path of least resistance. Take gravity for example. It's easier to fall down than to go up. In electricity, it's natural for electrons to flow from a point of high resistance (like insulators--carpet fibers in our example) to a point of low resistance (like metal--the doorknob). To be exact, it's the path of least potential (loosely, electric potential is the pressure that can push electric charges to different locations) that electricity wants. The flow from high to low potential is called "current." A sudden flow of surface charge, meaning a large difference of potential values, meanwhile, causes discharge. Thus the term electrostatic discharge.

Perhaps the most famous, and deadliest example of ESD is lightning. The insulator in this case is air. The low resistance point is the earth, appropriately named "ground." The difference between air and ground in terms of potential runs into millions of volts. The resulting current that flows between air and ground heats the air, causing an explosive release of energy.

And you expected sparks would be flying on your first date? Here's a tip: set it during the dry season, comb your hair often, go traipsing on the carpet and reach for the doorknob together. How is this so?

Walking on the carpet during the dry season generates 35,000 volts of static electricity. In humid atmosphere, it's around 1,500 volts. Combing your hair (use plastic comb) adds a few thousand volts more. Humidity reduces potential levels because of the presence of water particles in the air which may neutralize the static charge that you've been trying hard to gather. Metals are the best conductors of electricity, and the static you have built up would flow abruptly.

Now if you ask where you can buy sparks, good news: it's free. Like blind dates, expect irritation or shock though.

Reference: ESD Association, Fundamentals of ESD

Next on Skythologies: Molecula, Muyak and the quantum promise

This entry was posted by sky, on Tuesday, June 21, 2005. You can leave your response.