Teledyne 9110T - Nitrogen Oxides Analyzer - Manual (Page 370)

Model 9110T NOx Analyzer Primer on ESD
Teledyne Analytical Instruments 370
Wrist Strap
Protective Mat
Ground Point
Figure 14-2: Basic anti-ESD Workbench
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.