![]() ![]() The degradation in some devices may not become evident until well into their service life. ![]() These invisible forms of ESD can cause outright device failures, or less obvious forms of degradation that may affect the long term reliability and performance of electronic devices. Some devices may be damaged by discharges as small as 30 V. A person carrying a relatively small electric charge may not feel a discharge that is sufficient to damage sensitive electronic components. However, many ESD events occur without a visible or audible spark. ![]() This can cause minor discomfort to people, severe damage to electronic equipment, and fires and explosions if the air contains combustible gases or particles. The most spectacular form of ESD is the spark, which occurs when a heavy electric field creates an ionized conductive channel in air. This is a known hazard for most spacecraft. This causes increasing surface and deep charging. For example, charged regions on the surfaces of styrofoam cups or bags can induce potential on nearby ESD sensitive components via electrostatic induction and an ESD event may occur if the component is touched with a metallic tool.ĮSD can also be caused by energetic charged particles impinging on an object. An ESD event may occur when the object comes into contact with a conductive path. Even though the net electrostatic charge of the object has not changed, it now has regions of excess positive and negative charges. ![]() The presence of the charged object creates an electrostatic field that causes electrical charges on the surface of the other object to redistribute. This occurs when an electrically charged object is placed near a conductive object isolated from the ground. In all these cases, the breaking of contact between two materials results in tribocharging, thus creating a difference of electrical potential that can lead to an ESD event.Īnother cause of ESD damage is through electrostatic induction. Examples of tribocharging include walking on a rug, rubbing a plastic comb against dry hair, rubbing a balloon against a sweater, ascending from a fabric car seat, or removing some types of plastic packaging. Static electricity is often generated through tribocharging, the separation of electric charges that occurs when two materials are brought into contact and then separated. One of the causes of ESD events is static electricity. 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.ĮSD simulators may be used to test electronic devices, for example with a human body model or a charged device model. These can suffer permanent damage when subjected to high voltages. Other forms of ESD include corona discharge from sharp electrodes, brush discharge from blunt electrodes, etc.ĮSD can cause harmful effects of importance in industry, including explosions in gas, fuel vapor and coal dust, as well as failure of solid state electronics components such as integrated circuits. Electric sparks require a field strength above approximately 4 × 10 6 V/m in air, as notably occurs in lightning strikes. Electrostatic discharge ( ESD) is a sudden and momentary flow of electric current between two differently-charged objects when brought close together or when the dielectric between them breaks down, often creating a visible spark associated with the static electricity between the objects.ĮSD can create spectacular electric sparks ( lightning, with the accompanying sound of thunder, is an example of 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. ![]()
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