Electrostatic discharge (ESD) is one of the most significant factors leading to damage and failure of a wide variety of electronic components. This damage results in increased manufacturing and warranty costs, and unreliable products are the result.
Static Electricity is a common occurrence in everyday life. As we go about our lives, we all experience mild electric shocks from objects around us. Friction between, and separation of, dissimilar materials, causes electrons to be transferred from one object to another. This in balance of electrons between objects causes the objects to be at different electrical potentials, relative to one and other. When two bodies of opposite charge, or a charged and an uncharged body come into contact with each other, electrons flow from one body to the other very rapidly, and can generate very high current flows and heat for a very short period of time.
Synthetic materials like those clothes, carpets and furniture are made of are bad offenders, particularly in very dry weather conditions. They are very good insulators and when a charge is built up on them, it will not flow away due to leakage, it must be discharged by coming into contact with another body. These materials generate high voltage Static Electricity charges when rubbed together. All of us have had a mild electric shock from a door handle, a metal cabinet or a similar object, after we have walked some distance over a carpet or vinyl floor, or moved around on a plastic chair. The motion of our body clad in clothing made of synthetic cloth causes us to be charged to a high potential relative to surrounding objects. These mild electric shocks cause us some discomfort when they occur but this is insignificant when we look at the damage they do to modern electronic components.
EDS becomes a more serious problem on low humidity days when the lack of moisture permits a more rapid static charge build-up.
These five little known facts about ESD can make a big difference in its elimination:
1. ESD often can’t be seen, heard or felt.
2. Devices can be stressed or damaged even without physical contact.
3. Smaller, miniaturized devices are sensitive to 50 volts or less.
4. ESD problems can occur to devices at anytime – even after they are installed on circuit cards.
5. Everyone involved in the handling, installing, test, shipping and storing of electronic devices or boards must take preventative measures against the threat of ESD.