What is Electrostatic discharge?
Electrostatic discharge, which shorted for ESD, is the sudden flow of electricity between two electrically charged objects caused by contact, an electrical short, or dielectric breakdown. A buildup of static electricity can be caused by tribocharging or by electrostatic induction. The ESD occurs when differently-charged objects are brought close together or when the dielectric between them breaks down, often creating a visible spark.
ESD can create spectacular
electric sparks (thunder and lightning is a large-scale ESD event), but also
less dramatic forms which may be neither seen nor heard, yet still be large
enough to cause damage to sensitive electronic devices. Electric sparks require
a field strength above approximately 4 kV/cm in air, as notably occurs in
lightning strikes. Other forms of ESD include corona discharge from sharp
electrodes and brush discharge from blunt electrodes.
ESD can cause a range of harmful effects of importance in
industry, including gas, fuel vapor and coal dust explosions, as well as
failure of solid state electronics components such as integrated circuits.
These can suffer permanent damage when subjected to high voltages. Electronics
manufacturers therefore establish electrostatic protective areas free of
static, using measures to prevent charging, such as avoiding highly charging
materials and measures to remove static such as grounding human workers,
providing antistatic devices, and controlling humidity.
ESD simulators may be used to test electronic devices, for
example with a human body model or a charged device model.