Hi Bill,
The reason for the contact discharge ESD test is to simulate discharges
that can result from handling of the product, such as our finger touching,
connector connect/disconnect, tools pick up the product, etc. So if
normally we have a chance of reaching deep into the vent and contacting it
inside, then we need to do that. If not, then no need to do so. If the
vent is smaller than our small finger, I can imagine there's no chance that
we can reach deep into the vent, unless the product is normally handled by a
tool which is small enough to get into the vent. Then you have to do it.
BTW, the air discharge and contact discharge are simulating two
different discharge phenomena. So it's not necessary that your contact
discharge areas and air discharge areas have to follow up on each other.
Alfred Ip
Trimble Navigation Ltd.
> ----------
> From: Jacowleff, Bill[SMTP:[email protected]]
> Reply To: Jacowleff, Bill
> Sent: Friday, September 24, 1999 1:02 PM
> To: Emc-Pstc (E-mail)
> Subject: Direct Contact Discharge into Vents to EN61000-4-2
>
>
>
>
> > -----Original Message-----
> > From: Jacowleff, Bill
> > Sent: Friday, September 24, 1999 3:53 PM
> > To: EMC POST GROUP (E-mail)
> > Subject: Direct Contact Discharge into Vents to EN61000-4-2
> >
> >
> >
> > Greetings to all:
> >
> > I am testing a product that has small plastic modular housing with
> > vents to EN61000-4-2.
> >
> > At 8 kV Air discharge I have discharge to the open vents which is
> > fine, the PCB is protected on the perimeter and tolerates this well.
> >
> > However my question is with the Direct Contact Discharge to these
> > vented areas. I am under the impression of
> > where I have an air discharge I am to follow-up that area with a
> > Direct Contact Discharge. In this particular case the vents
> > are large enough to allow the tapered Direct Contact Discharge Tip
> > to fit deep enough in the vents, passing the perimeter protection
> > on the PCB and come in direct contact with one component on the PCB.
> >
> > So my question is How far should the Direct Contact Discharge Tip be
> > inserted into a vent? As far as it will reach? Or should the Direct
> > Contact Discharge Tip be limited to touching the outside wall of the
> > module near the vent?
> >
> > Thanks for your reponse in advance.
> >
> > Best Regards,
> >
> > Bill Jacowleff
> > VDO Control Systems
> > Airpax Instruments
> > 150 Knotter Drive
> > Cheshire, CT 06410
> > Phone: 203 271-6394
> > FAX: 203 271-6200
> > [email protected]
> >
>
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