Log in

ISM Article

Protect Your Devices from EDS

21 Jan, 2010 By: Don Meis imageSource

Protect Your Devices from EDS

We’re all familiar with the simple electro magnetic shock
we can get from walking across a carpeted room. Unfortunately, that same energy
has the ability to damage internal parts of office imaging equipment which can
lead to intermittent device failures. Electro Static Discharge or ESD is the
release of stored energy (static electricity) between two points with different
potential voltages. Ideally, special precautions should be taken to avoid ESD,
especially with Printed Circuit Boards (PCB) & subassemblies that contain
components that are ESD sensitive.

Let’s start with a little science, getting a better understanding of how these
voltages are generated. Static electricity is most commonly created by friction
or separation.  The amount of static electricity generated depends on the
materials subjected to that friction or separation. Another factor is the amount
of humidity in the air.  As we are in the winter months, low humidity (dry air)
will increase the amount of static charge created. Most boards can be damaged or
harmed with a voltage of 30 volts or more, while hard disk drive components can
be harmed with less than 10 volts.


For example, something as simple as walking across carpet,
vinyl floors, or even working at a certain bench can generate as much as 12,000
volts!  What this means is that the circuit board or Hard Drive that your
service technician just picked up could now be permanently damaged. That is
costly so precautions are in order to help avoid that outcome.

Precautions field service technicians should take:


• Awareness of what can happen

• Use ESD mats and wrist straps when installing/removing
circuit board or sensitive component’s

• Transport circuit boards in ESD bags or cases

• Minimize movement while handling unprotected boards

• Place only the board in ESD protective packaging – other
objects such as paper, plastic bags, generate ESD that can damage the board

The use of a wrist strap is one of the most effective means to reduce the
chances of ESD damage to a PCB. Neutralizing the potential voltage differences
to a common point ground will prevent damage to the board.  Wrist straps should
be used at all times by the Field Engineer (FE) while handling PCB’s. Also, once
the PCB is removed from the protective packaging, the FE should reduce the
amount movement while handling the unprotected board.


Get the 1-2-3 on ESD

1 Integrated circuits are made from semiconductor materials such as silicon
and insulating materials such as silicon dioxide. Either of these materials can
suffer permanent damage when subjected to high voltages; as a result there are
now a number of antistatic devices that help prevent static build up.

2.More specifically, one of the causes of ESD events is static electricity. This
is often generated through tribocharging, the separation of electric charges
that occurs when two materials are brought into contact and then separated.
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


3. Regarding precautions, due to the dielectric nature of
electronics component and assemblies, electrostatic charging can not be
completely prevented during handling of devices. ESD prevention activities are
therefore important with those processes where the component is touching on
equipment surfaces. Interestingly, humid conditions prevent electrostatic charge
generation because the thin layer of moisture that accumulates on most surfaces
serves to dissipate electric charges.


Don Meis is the Service Director of Hytec Dealer
Services Inc, located in Florida.  Hytec is the industry leader In Circuit board
repair and logistic services for the office imaging equipment industry. Visit
www.hytecrepair.com. To learn more
about ESD and ESD protection, go to



WebinarCase Studies and White PapersSand Exchange Blog

imageSource Magazine Quick Links
Upcoming Events
ITEX Expo & Conference
©2015 Questex, LLC. All rights reserved
Reproduction in whole or part is prohibited
Please send any technical comments or questions to our webmaster