Absolutely right.

The old MIL-STD-2000A requirements were as follows:

"Resistance between the tip of the hot soldering iron and
the workstation ground shall not exceed 5.0 ohms.  The
potential difference between the workstation ground and the
tip of the hot soldering iron shall not exceed 2 millivolts RMS."

Granted, maybe 2 millivolts is a little tight.  I once asked
where these limits came from, and apparently the soldering
iron manufacturers told the spec writers what they could
meet.  But still, the intent is obvious - you don't want to
be squirting electrons into whatever you're soldering.

-Joe

-----Original Message-----
From: Guy Ramsey [mailto:[log in to unmask]]
Sent: Tuesday, February 10, 2004 9:00 AM
To: [log in to unmask]
Subject: Re: [TN] iron tip potential


WRONG!
We are not talking ESD here. This guy has an electrical problem. The
voltages are not nearly as transient as static discharges. Anything
greater that the junction voltage can reverse bias a semiconductor and
blow it away. This guy can apply 24 volts to any random point on his
circuit (the power-supply voltage in the Weller Iron he is using).

> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Dehoyos, Ramon
> Sent: Tuesday, February 10, 2004 8:47 AM
> To: [log in to unmask]
> Subject: Re: [TN] iron tip potential
>
>
>         Pankaj:
>         That small potential difference will not damage
> anything. The voltage needs to be well over 100 in order to
> start being a problem for some devices. In my experience,
> voltages over 1000 volts are the ones that do damages. Most
> of new devices are designed to withstand ESD damage to some
> extent. Perhaps some will disagree with me.
>         Regards,
>         Ramon
>
> > -----Original Message-----
> > From: Blair K. Hogg [SMTP:[log in to unmask]]
> > Sent: Tuesday, February 10, 2004 7:08 AM
> > To:   [log in to unmask]
> > Subject:      Re: [TN] iron tip potential
> >
> > I would say that they should be at the same potential.
> >
> > Have you tried to determine the source of the difference?
> >
> > Blair Hogg
> > QA Manager
> > GAI-Tronics Corp.
> >
> > >>> [log in to unmask] 02/10/04 04:27 AM >>>
> > Dear all, hello
> >
> > My question about the potential deference between the
> soldering iron
> > tip
> and
> > the ESD grounded mat. I observed that it is about 20 to 30
> volts, is
> > it
> safe
> > for ESD sensitive device? and is it mandatory to keep the
> iron tip on
> > same potential with ESD grounded mat.
> >
> >
> >
> > Pankaj Karnwal
> > Jr. Engineer QA
> >
> > Barco Electronics System  (P) Ltd.
> >
> > WWW.barco.com
> > mailto:[log in to unmask]
> >

>

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