[sdiy] OT: Where to get cheap ESD safe electronics parts drawers?

Scott Gravenhorst music.maker at gte.net
Sun Mar 12 13:55:00 CET 2017


Some years ago when I worked for DEC we all watched a film (yes, 16mm film in a projector)
about static sensitivity.  Two engineers were positioned several feet apart.  One engineer
had an MOS transistor in a tester which showed it to be good.  The engineer then simply
tossed the device through and the other engineer caught it.  Both had bare hands.  The 2nd
engineer tested it with another tester at his end of the bench.  They tossed the device back
and forth and it didn't take but of 5 or 6 tosses before the device showed bad in the
tester.  All it took was passing through the air to generate and/or collect enough static
electricity to destroy the device.  Very convincing film.  I never worked on MOS devices
without a grounding strap.  This is not mythology, it's science.  Surely if you work on MOS
devices in the Amazon rain forest, your chances of destroying a device by mishandling are
lower, but the chance still exists.  It's so easy to use a ground strap that it's silly not
to do so.

ASSI <Stromeko at nexgo.de> wrote:
>On Sunday, 12 March 2017 01:10:48 CET Tom Wiltshire wrote:
>> I think the risk of chips dying from static is somewhat overplayed.
>
>It isn't.  I've seen my share of parts returned from the field with sometimes 
>horrible damage.  Often enough we don't get to learn the reason other than 
>that it was an ESD damage and not outr fault, but in the few cases where we 
>did it was usually quite minor things.
>
>Now, as all things the ESD damage doesn't come in a single form.  Sometimes 
>the chip just doesn't conform to specs anymore (higher leakage or offset for 
>instance), sometimes you've reduced the lifetime  and only then you get to the 
>point where the chip is immediately destroyed.  The chips have different 
>vulnerabilities when they are soldered in vs. when you handle them before, so 
>the details of what you do when matter quite a lot.
>
>> It's a
>> good way to sell you more stuff, and perhaps in a production environment
>> where you're handling thousands each day the numbers start to stack up, but
>> for an individual? Seems unlikely.
>
>If you live in a climate where the relative humidity goes below 30% or so 
>regularly you'd have significant worries for instance.  The same if your 
>floors are made of some plastic or your work chair covers or clothing are 
>synthetic.  You like to have a fan next to your desk?  You may be blowing 
>charges around.
>
>The ESD protection built into the chips varies, but for consumer stuff it's 
>typical to protect for between 500V…1.5kV HBM (human body model).  That you 
>can exceed without even trying.
>
>> I'm quite willing to hear why that's all nonsense though.
>
>Well, you don't need to have the full monty like you were a certified 
>manufacturing shop.  But the basics should be covered: anti-static work area 
>and tools, potential equalization for everything on the work desk (including 
>yourself, please don't skip the protective resistor on the wrist strap 
>connection) and just keep everything in ESD bags (preferrably the ones you got 
>the parts in).  Anything you bring to the work area must be equalized to 
>potential before resuming work, including yourself if you stand up and fetch 
>something.
>
>
>Regards,
>Achim.
>-- 
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-- ScottG
________________________________________________________________________
-- Scott Gravenhorst
-- http://scott.joviansynth.com/
-- When the going gets tough, the tough use the command line.
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