ESD GUN

[blanko]

We are in the middle of doing our compliance testing and failing on
the ESD test. For the air discharge with the ESD gun set at 8 kV
what is the minimum distance between the tip of the gun and any metal
contact that will prevent arching/discharge?

-Mike.

[hrho...@att.net]

It depends on temperature, air pressure, humidity, as well as phase of
the moon, position of the stars and planets. Sorry - I couldn't
resist. Try and engineering handbook.

[blanko]

Should I be trying to prevent the 8kV discharge or route the discharge
to ground? Any comments on this would be appreciated.

-M

[Wimpie]

Hello,

When you completely fill possible creepage paths (resin, glue, etc),
you can block it from entering. You will only get a kind of corona
discharge that is mostly not harmful.

When it is not possible to block it (for example a LED in a front
panel opening), you might put a grounded ring around the LED. So that
the arc strikes the ring instead of the lead of the LED. Off course,
the ground path must be large/heavy enough to divert the ESD from
sensitive circuits.

The minimum creepage distance depends on the surface material and
surface conditions. For 8 kV level, I would think of about 8mm or
more.

Hopes this helps a bit.

Best regards,

Wim
PA3DJS
www.tetech.nl
remove abc from the mail address.

[blanko]

Thanks for the posts guys! I appreciate it deeply!

-M