The Causes of ESD Effect
The Causes of ESD Effect
Electrostatic
discharge (ESD) is the
sudden flow of electricity between two
electrically charged objects caused by contact, an electrical short, or dielectric breakdown.
One of the causes of
ESD events is static electricity. Static electricity
is often generated through tribocharging,
the separation of electric charges that occurs when two materials are brought
into contact and then separated. 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. 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.
Another cause of ESD damage
is through electrostatic
induction.
This occurs when an electrically charged object is placed near a conductive
object isolated from the ground. The presence of the charged object creates an
electrostatic field that causes electrical charges on the surface of the other
object to redistribute. Even though the net electrostatic charge of the object
has not changed, it now has regions of excess positive and negative charges. An
ESD event may occur when the object comes into contact with a conductive path.
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.
ESD can also be caused
by energetic charged particles impinging on an
object. This causes increasing surface and deep charging. This is a known hazard for most spacecraft.