2
When is a Static Charge Formed?
One can never be sure that the human body or the material and tools which one is using are not
electrostatically charged.
Small charges up to 100 V are very common; these can, however, very quickly rise up to
35 000 V!
Examples of static charge:
–
Walking on a carpet
up to
35 000 V
–
Walking on a PVC flooring
up to
12 000 V
–
Sitting on a cushioned chair
up to
18 000 V
–
Plastic desoldering unit
up to
8 000 V
–
Books, etc. with a plastic binding
up to
8 000 V
–
Plastic bag
up to
5 000 V
–
Plastic coffee cup
up to
5 000 V
3
Important Protective Measures against Static Discharge
•
Most plastic materials are highly susceptible to static charge and must therefore be kept as
far away as possible from ESDs!
•
Personnel who handle ESDs, the work table and the packing must all be carefully grounded!
4
Handling of ESD Modules
•
One basic rule to be observed is that electronic modules should be touched by hand
only if this is necessary for any work to be done on them. Do not touch the component
pins or the conductors.
•
Touch components only if
– the person is grounded at all times by means of a wrist strap
or
– the person is wearing special anti-static shoes or shoes with a grounding strip.
•
Before touching an electronic module, the person concerned must ensure that (s)he is
not carrying any static charge. The simplest way is to touch a conductive, grounded
item of equipment (e.g. a blank metallic cabinet part, water pipe, etc.) before touching
the module.
•
Modules should not be brought into contact with insulating materials or materials which
take up a static charge, e.g. plastic foil, insulating table tops, synthetic clothing, etc..
•
Modules should only be placed on conductive surfaces (table with anti-static table top,
conductive foam material, anti-static plastic bag, anti-static transport container).
•
Modules should not be placed in the vicinity of visual display units, monitors or TV sets
(minimum distance from screen > 10 cm).
The diagram on the next page shows the required protective measures against electrostatic
discharge.
ESD Guidelines
ii
C79000-D8076-C333-01
