25 Jul
2012
25 Jul
'12
12:33 a.m.
On Tue, 24 Jul 2012, Chuck Guzis wrote:
On 24 Jul 2012 at 21:29, jim s wrote:
Lithium coin cell batteries and real-time clock modules (with embedded
batteries).
As Will pointed out, if the bags are too conductive (just like the black
conductive bags), they don't really protect against external ESD.
I have some very old foil-type antistatic bags that have a plastic layer
on the inside and a stiff foil on the outside. They even hold their shape
if you bend them. The most common type I see today are the metalized film
type bags though, and those are safe for use with boards that use lithium
coin cells.
He was sitting at his desk with a voom and no way
he could find any
conductivity in the bags. No good. Never mind they only needed to be
there for shipping, he never inventoried them at his end. Never mind
this was irrelevant.
Never mind that the mylar bags we used had no conductivity except in
the megohms either.
Clearly, the only safe anti-static bag (taking a cue from an earlier
post) is one filled with water.
So why aren't aluminized foil bags used more? I have a few-- basically
a sandwich made of foil sandwiched between an outer envelope of PE sheet
and an inner linner of bubble material. Totally opaque.