Electrostatic
Discharge (ESD) Protection
It is important to consider
antistatic, conductive or ESD
packaging when it comes to the
care and handling of expensive
electronic devices. We have
all seen static electricity
in the form of lightning or
perhaps felt the zap when reaching
for a door knob. Similar types
of electrical charges can have
an effect on the electronic
components in every day production,
handling, shipping and warehousing.
Unfortunately, their effect
is much more hazardous and not
as readily apparent. Static
electricity is an electrical
charge at rest. Static electricity
is most commonly created by
friction and separation. Friction
causes heat, which excites the
molecular particles of the material.
When two materials are then
separated, a transfer of electrons
from one material to the other
may take place.
Because electrons transfer,
the absence or surplus of electrons
creates an electrical field
known as static electricity.
The amount of static electricity
generated depends upon the materials
subjected to friction or separation,
the amount of friction or separation
and the relative humidity of
the environment. Common plastic
generally will create the greatest
static charge. Low humidity
conditions such as those created
when air is heated during the
winter will also promote the
generation of significant static
electrical charges.
Materials that easily transfer
electrons (or charge) between
atoms are called conductors
and are said to have “free”
electrons. Some examples of
conductors are metals, carbon
and ESD or commonly known as
static dissipating films.
Materials that
do not easily transfer electrons
are called insulators, they
include glass and air. Both
conductors and insulators can
be “charged” with
static electricity. When a conductor
is charged, the free electrons
give it the ability to discharge
rapidly when it comes close
to another conductor with a
different potential. Many of
the common activities you perform
daily may generate charges on
your body that are potentially
harmful to components, for example:
Walking across a carpet, 1,500
to 35,000 volts; Walking over
untreated vinyl floor, 250 to
12,000 volts; Worker at a bench,
700 to 6,000 volts; Picking
up a common plastic bag from
a bench, 1,200 to 20,000 volts.
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