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Simply touching a grounded piece of metal is insufficient. While this may temporarily
bleed off static charges present at the time, once you stop touching the grounded metal new
static charges will immediately begin to re-build. In some conditions, a charge large enough
to damage a component can rebuild in just a few seconds.
Always store sensitive components and assemblies in anti-ESD storage bags or bins:
Even when you are not working on them, store all devices and assemblies in a closed anti-
Static bag or bin. This will prevent induced charges from building up on the device or
assembly and nearby static fields from discharging through it.
Use metallic anti-ESD bags for storing and shipping ESD sensitive components and
assemblies rather than pink-poly bags. The famous, "pink-poly" bags are made of a plastic
that is impregnated with a liquid (similar to liquid laundry detergent) which very slowly
sweats onto the surface of the plastic creating a slightly conductive layer over the surface of
the bag.
Never use ordinary plastic adhesive tape near an ESD sensitive device or to close an
anti-ESD bag. The act of pulling a piece of standard plastic adhesive tape, such as Scotch
tape, from its roll will generate a static charge of several thousand or even tens of thousands
of volts on the tape itself and an associated field effect that can discharge through or be
induced upon items up to a foot away.
11.5. BASIC ANTI-ESD PROCEDURES FOR ANALYZER REPAIR
AND MAINTENANCE
11.5.1. WORKING AT THE INSTRUMENT RACK
While this layer may equalizes any charges that occur across the whole bag, it
does not prevent the build up of static charges. If laying on a conductive,
grounded surface, these bags will allow charges to bleed away but the very
charges that build up on the surface of the bag itself can be transferred through the
bag by induction onto the circuits of your ESD sensitive device. Also, the liquid
impregnating the plastic is eventually used up after which the bag is as useless for
preventing damage from ESD as any ordinary plastic bag.
Anti-Static bags made of plastic impregnated with metal (usually silvery in color)
provide all of the charge equalizing abilities of the pink-poly bags but also, when
properly sealed, create a Faraday cage that completely isolates the contents from
discharges and the inductive transfer of static charges.
Storage bins made of plastic impregnated with carbon (usually black in color) are
also excellent at dissipating static charges and isolating their contents from field
effects and discharges.
When working on the analyzer while it is in the instrument rack and plugged into a
properly grounded power supply.
1. Attach your anti-ESD wrist strap to ground before doing anything else.
Use a wrist strap terminated with an alligator clip and attach it to a bare metal
portion of the instrument chassis. This will safely connect you to the same
ground level to which the instrument and all of its components are connected.
®
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