You have probably experienced static electricity in your daily life at one time or another. Walking along a carpeted floor in the winter in a heated environment will generate enough static electricity to shock you when you touch a door knob or another metal object. Maybe you have seen or heard it in action in your laundry when clothes are removed form the drying cycle. The most spectacular example of static discharge is a lightning bolt ripping through the night sky! The popping sound it makes and the light that is emitted as the static electricity is discharged.

These generated charges can be very damaging to electrical components/circuit boards that are sensitive to electrostatic discharge. It also possible for electronic devices to be damaged by ESD that is not noticed by the human body. Even though you think you have not generated any static electricity, you have. It’s just not powerful enough to be detected by our own touch.

Damage from electrostatic discharge events, ESD might not show up immediately as a failure. But over time if the circuit board or components are subjected to more ESD events a failure could certainly occur. A catastrophic failure, which is failure immediately following an ESD event is not uncommon but more likely, is for some latent damage to occur. The board or device is still functional after an ESD event, but some sensitive circuitry or component has been damaged and a failure might occur in the near future.

There are ways to prevent or control static electricity. The relative humidity or RH has direct correlation to the generation of static electricity. When RH is low, below 40%, the amount of charge accumulated is greatly increased. The optimum RH seems to be in the 40 to 60% range. Static control mats which utilize a grounding strap connected to a good ground, like a wall outlet. There is anti-static clothing and footwear available to help keep ESD from occurring. The anti-static wrist or ankle strap is the most common tool used to prevent ESD damage. It is lightweight portable and easily taken from place to place. It has a conductive,adjustable wristband attached to to flexible cable with an alligator clip on the end used for clamping on to a good grounding point.

If you are working on a printer or other device with sensitive circuitry you can attach the strap to the metal frame to ensure you stay at the same potential, thus not building up any damaging static electricity. If you do not have any of these devices available to use and you are working in an environment that is conducive to generating static electricity, keep touching a good grounding point. The metal frame of the device/printer you are working on will work to discharge any charges you are accumulating. The use of antic-static packaging (ESD bags) to protect and handle circuit boards is a good way to keep them from being damaged. Not only will this protect the board, it will protect you from having to pay for something that was working fine before you got there!