Remember at time testing at a manufacturing location down south. Don't
know if it was humidity but we were the first to know that a rain storm was
headed our way. There was a dramatic change in the ESD discharge and response
characteristics before and during the downpour. Same for a trip in Japan -
which is very humid to start with.
No attempt to explain - just presenting a couple of experiences.
Wasn't really an obstacle, we were easily able to locate and resolve the
problem regardless of the outside weather. PS neither of the locations had air
conducting or humidity control so other than physical raindrops we had the same
temperature and humidity as outdoors.
I dawns on me, that to work out the variability in weather in Japan we
moved into their sound chamber, that for some reason did have humidity control
- not a clue why.
Gary
-----Original Message-----
From: bogdan matoga [mailto:[email protected]]
Sent: Wednesday, June 12, 2002 12:01 PM
To: Gibling, Vic
Cc: [email protected]
Subject: Re: An ESD question
Vic:
The ambient relative humidity should have no impact on the performance of the
gut but only on the generation of static charges. So, to improve the
performance in the field, I would suggest that you increase the R.H. at the
customer site(s) to about 50% which would eliminate the generation of
electrostatic charges and consequently the problems. This will give you time to
work on the equipment to minimize ESD susceptibility.
By the way, lower R.H. also occurs at low tamperatures.
Please let me know how things work out.
Bogdan.
Gibling, Vic wrote:
> Dear Group
>
> I tried to find David Pommerenke article's in the Journal of ESD on the Web
> but alas no downloadable version was found, so may I ask the group a
> question?
>
> We have an ESD field failure which is occurring in dry hot countries ( no
> surprise )which can be recreated with an ESD of -800V. In an attempt to get
> a high incidence of discharges we used a dehumidifier to create a dry
> environment. The result was a reduction in discharges.
>
> Thinking the problem through -now- as a dry atmosphere will encourage the
> production of high level ESD and a humid environment inhibits the charge to
> a lesser level, presumably because it 'leaks' away. Then is it wrong for us
> to attempt to 'dry' the local atmosphere in the hope of gaining consistent
> ESD from an ESD gun, that is to say the more humid the environment the more
> efficiently the discharge will transfer to the victim?
>
> Incidentally, to add to the thread regarding intermediate level testing for
> ESD and EFT. This exercise has revealed different failure mechanisms at
> different ESD levels.
>
> Your views would be appreciated.
>
> Vic Gibling
> Compliance Engineer
> Marconi Applied Technologies
>
>
>
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