How do you tell an anti-static material?

[mario]

Dear all,


I know this subject is really just marginal to this newsgroup.
Still, I don't now a better place and a smarter bunch, so here it goes: I
have always been wondering how do you know whether a plastic bag is
anti-static or not? I tried to use my digital multimeter to measure
resistance, but any static bag I have tried, shows infinite resistance - an
insulator. So, obviously, that wasn't the way.

But which is it, then? How does your average Joe with a soldering iron (and
little more) tell whether his precious electronic wares are in a safe place?


grateful in advance!



mario

 

[mario]

"en" <res7nl33@verizon.net> wrote in message
news:ATw_c.2428$j62.58@trnddc04...

To test a plastic bag for anti-static properties, you look for it's
tribo-electric
charge abilities. You need a few meters; surface resistivity meter and
electrostatic field meter.
you take the surface resistivity meter and put it on the material .
Thank you. What exactly is a surface resistivity meter, and how do I

improvise one with a digital multimeter?I guess the electrodes should be
made in a certain shape.

Any material less than or equal to10^6 ohms is considered conductive,
so it's anti-static safe. Any material less than or equal to 10^8 is
dissipative,
so it;s considered anti-static safe. anything above 10^8 is no good, it's
hot plastic, will damage ICs.
Are those figures relative to a certain profile/cross section? As in 10^8/m

or 10^8/m2 ?

You take the electrostatic field meter and measure ground.
To discharge it, I guess...
Take a bag in question and rub it 3 times with another same bag.
move the bag w/ in 1" of the electrostatic field meter. If the meter say
anything
above 100 volts it's not good and will damage ICs.
How do I improvise a simple an electrostatic field meter? A voltmeter with

very high impedance, and one spheric electrode, perhaps?

Look in a databook for an ESD section. TLL is damaged w/ 2000 or more
volts of static. CMOS is damaged with more than 500 volts of static
discharge.

 

[Al]

In article <Rdq_c.24489$g4.460185@news2.nokia.com>,
"mario" <gianmarioRE.scottiMO@nokiaVE.com> wrote:

Dear all,


I know this subject is really just marginal to this newsgroup.
Still, I don't now a better place and a smarter bunch, so here it goes: I
have always been wondering how do you know whether a plastic bag is
anti-static or not? I tried to use my digital multimeter to measure
resistance, but any static bag I have tried, shows infinite resistance - an
insulator. So, obviously, that wasn't the way.

But which is it, then? How does your average Joe with a soldering iron (and
little more) tell whether his precious electronic wares are in a safe place?


grateful in advance!



mario

Put a neon bulb into the bag. Make sure the leads are well separated.
Rub the bag with a piece of wool. If the bulb flashes, the bag is not
anti-static. Not foolproof, but cheap and easy.

Al

 

[mario]

"Al" <no.spam@wanted.com> wrote in message
news:no.spam-94A708.10592505092004@news.verizon.net...

Put a neon bulb into the bag. Make sure the leads are well separated.
Rub the bag with a piece of wool. If the bulb flashes, the bag is not
anti-static. Not foolproof, but cheap and easy.

And by neon bulb I guess you mean the household low-pressure mercury vapor

fluorescent light, I suppose? This seems like the best, most elegant method
I have ever heard or thought of. Many thanks, Al!!!

 

[en]

"mario" <gianmarioRE.scottiMO@nokiaVE.com> wrote in message
news:52A_c.24494$g4.460090@news2.nokia.com...

"en" <res7nl33@verizon.net> wrote in message
news:ATw_c.2428$j62.58@trnddc04...
To test a plastic bag for anti-static properties, you look for it's
tribo-electric charge abilities. You need a few meters; surface
resistivity meter and electrostatic field meter. you take the surface
resistivity meter and put it on the material .

Thank you. What exactly is a surface resistivity meter, and how do I
improvise one with a digital multimeter? I guess the electrodes should be
made in a certain shape.

Do a web search and you will see what a surface resistivity meter is.
It is a precise resistance meter that measures from 10^1 ohms to
10^12 ohms. You can not modifiy a typical ohm meter to work as a
surface resistivity meter, since the typical DMM can not measure into
the megaohm range. Look at the ANSI / EOS / ESD specifications.

Any material less than or equal to10^6 ohms is considered conductive,
so it's anti-static safe. Any material less than or equal to 10^8 is
dissipative, so it;s considered anti-static safe. anything above 10^8
is no good, it's hot plastic, will damage ICs.

Are those figures relative to a certain profile/cross section? As in
10^8/m
or 10^8/m2 ?

Sorry bout that. 10^6 ohms = 1,000,000 ohms. , 10^3 = 1,000 ohms , etc

You take the electrostatic field meter and measure ground.

To discharge it, I guess.

No. You measure a Ground Point to Zero out the meters.

Take a bag in question and rub it 3 times with another same bag.
move the bag w/ in 1" of the electrostatic field meter. If the meter say
anything above 100 volts it's not good and will damage ICs.

How do I improvise a simple an electrostatic field meter? A voltmeter with
very high impedance, and one spheric electrode, perhaps?

Built an ESD Field meter , w/ accuracy? I have not seen a kit, since this
is a thing you play w/ often. Take into consideration Classical
Electro-Statics
and Physics studies, Ohms Law, Gauss's Law.

What you can try is a very senstive MOSFET amplifier ckt.
The meter reading could be a microamp needle meter?
The snesor could be a small metal rod 3" long w/ a 1/2" metal ball
for an antenna.
my guess is now that I've said that, your going to ask me to provide a
circuit, which I am not going to, since I don't want to build one.

Look in a databook for an ESD section. TLL is damaged w/ 2000 or more
volts of static. CMOS is damaged with more than 500 volts of static
discharge.

 

[Ken Smith]

In article <Rdq_c.24489$g4.460185@news2.nokia.com>,
mario <gianmarioRE.scottiMO@nokiaVE.com> wrote:

Dear all,


I know this subject is really just marginal to this newsgroup.
Still, I don't now a better place and a smarter bunch, so here it goes: I
have always been wondering how do you know whether a plastic bag is
anti-static or not? I tried to use my digital multimeter to measure
resistance, but any static bag I have tried, shows infinite resistance - an
insulator. So, obviously, that wasn't the way.

But which is it, then? How does your average Joe with a soldering iron (and
little more) tell whether his precious electronic wares are in a safe place?

The pink bags feel a bit soapy.

With a very large contact area, you can sometimes see its resistance with
a meter.


Rub some non-antistatic plastic in your hair and then hold one end of the
bag and try to charge up the other end off the bag. If you can pick up
paper with the end of the bag its no good.


--
--
kensmith@rahul.net forging knowledge