Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 276)

ESD Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 258
W r is t S t r a p P r o t e c t iv e M a t
G r o u n d P o in t
Figure 11-2: Basic anti-ESD Work Station
For technicians that work in the field, special lightweight and portable anti-ESD kits are available from
most suppliers of ESD protection gear. These include everything needed to create a temporary anti-ESD
work area anywhere.
 Always wear an Anti-ESD wrist strap when working on the electronic assemblies of your
analyzer . An anti-ESD wrist strap keeps the person wearing it at or near the same potential as
other grounded objects in the work area and allows static charges to dissipate before they can
build to dangerous levels. Anti-ESD wrist straps terminated with alligator clips are available for
use in work areas where there is no available grounded plug.
Also, anti-ESD wrist straps include a current limiting resistor (usually around one meg-ohm) that
protects you should you accidentally short yourself to the instrument’s power supply.
 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.
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.
 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.