Although many people have heard or know about electrostatic discharge (ESD), there are still many facts about it that may surprise them. The reasons for this can include the many ESD myths/misconceptions still hanging around; another is the fact that ESD is a much more common effect than most people realize.
Some of those rather interesting (if not bizarre) facts about ESD include:
- High humidity environments increase the chances for ESD trouble/activity.
- Engaging in simple everyday acts can be considered “risky behavior” in the world of ESD susceptibility. Some of those acts (and the charges they can produce) include:
- Walking across a carpet (1,500V to 35,000V)
- Walking across a vinyl floor (250V to 12,000V)
- Utilizing vinyl envelopes (600V to 7,000V)
- Working on a polyurethane chair (1500V to 18,000V)
- All electronic components/parts have different relative sensitivities to ESD—why they cannot all be treated the same. Some electronic components (and their electronic susceptibilities) to watch out for include:
- CMOS (250 to 3000)
- SAW (150 to 500)
- VMOS (30 to 1800)
- EPROM (100 plus)
- Schottky Diodes (300 to 2500)
- Parts degraded/damaged by ESD may pass operational tests only to malfunction in the field when subjected to stresses. In other words, ESD damage is often difficult to diagnose/pinpoint.
- ESD protection devices should not be optional. ESD will cause damage most of the time unless managed properly.
- ESD is not a modern phenomenon; people have known about it for hundreds of years. For example, people in the 1800s took measures to make sure that black powder was safe from ESD.
- There are still many myths surrounding ESD. Touching metal objects to discharge oneself, for example, does not make one ready/safe to work on ESD-sensitive material. Body charges tend to rebuild right away.
- Inserting components into printed wiring boards (PWBs) do not make them ESD-proof.
- Different, especially-tailored ESD management strategies are necessary for different settings/needs.
- ESD problems can come from seemingly unlikely sources (e.g., charged plastic faceplates).
- ESD precautions are not taken by all manufacturers at all times. Because of costs involved, some manufacturers cut corners and, thus, see their products fail in the field.
- Everything is not presently known about ESD. Every once in a while something new is learned about ESD.
- ESD solutions don’t always come in neat, clearly-predictable “packages.” Periodically, creative solutions have to be found for previously un-encountered dilemmas.
- ESD management doesn’t always require expensive equipment and techniques. Sometimes what is required is avoiding simple errors of operation.
- Contact does not have to take place for ESD to be a problem. Sometimes just getting near an electric field can impart ESD effects.
ESD is arguably one of the most interesting aspects of electronics. Both experts and amateurs continue to be amused by what can be learned about ESD.