Conducting Bench Top Material
My electronic bench is an old commercial one made with steel stampings and
a steel top covered with Masonite. The Masonite is still in fair
condition. Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
Ironically, in the 1960's, Transite (asbestos) was sometimes used as a
covering for electronic benches as as it was resistant to molten solder. The
downside was that in sliding heavy equipment around, friable material could
be released.
Bruce Hunter
I use "Stat-Les" anti-static floor finish on my benches. You can find it at
Legge Systems,
http://www.leggesystems.com/c-177-static-control-floor-care-products.aspx
The price is pretty good for the 1 quart size bottles ($20 or so) and that
does a lot of benches.
-Bob, N3XKB
On Mon, Jan 25, 2010 at 8:42 AM, Brucekareen@aol.com wrote:
My electronic bench is an old commercial one made with steel stampings and
a steel top covered with Masonite. The Masonite is still in fair
condition. Although over the years the non-conductive top has been an
asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections could
not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
Ironically, in the 1960's, Transite (asbestos) was sometimes used as a
covering for electronic benches as as it was resistant to molten solder.
The
downside was that in sliding heavy equipment around, friable material
could
be released.
Bruce Hunter
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet. With that perspective, my
preferred benchtop is white Formica with a very, very slightly
pebbled surface. Very durable, including to molten solder, and small
parts show up well. I use rubberized "gunsmith" mats for preventing
scratches to delicate workpieces (these happen to be anti-static, but
that is not why I have them).
Other bench thoughts:
Bench depth is very important. I sometimes work on equipment that is
more than 24" deep, so I want at least 30" of clear space in front of
any obstructions (power strips, Variac, test equipment,
whatever). In the past, I used a "flying bridge" over the rear 18"
of a 48"-deep bench to elevate the test equipment, which worked very
well. Now I use 24" deep adjustable wire-rack shelving units behind
a 30" benchtop (As others have pointed out, you can do the same with
equipment racks -- I'm not a fan of rack-mounting test equipment
unless the racks are anchored and everything is on slides, which I
was not prepared to do). I don't have enough shop real estate to
have a permanent access aisle behind the test equipment, so the bench
and racks have large (5") locking polyurethane wheels and can be
pulled out relatively easily for reconfiguration. This provides
plenty of stability for electronic projects, but you wouldn't want to
mount a big vise on the bench and try to bend 1" rebar. For that, I
have a separate metalworking shop.
Bench height is also important. I prefer a tall bench, suited to
working standing or sitting on an ergonomic stool, so my bench top is
44" above the floor -- a bit below my standing elbow height.
Finally, one can never have too many power outlets, or too much
light, in a workshop. Lighting should be arranged so that it doesn't
cause specular reflections from the workpiece or the faces of test equipment.
Best regards,
Charles
In message 20100125182712.7014911B858@karen.lavabit.com, "Charles P. Steinmet
z" writes:
Bruce wrote:
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary [...]
My worktable has a surface of hardwood-floor-boards and a painted
steel profile on the front that I make point out of touching before
sticking my fingers into any sensitive circuits. Works for me.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Hi Charles,
I'm in a similar boat where I've worked with static sensitive parts without
any problems without having so much as put on a wrist strap. It's just
never been an issue, even with our RH sitting around 12% here in New
Mexico. I've been shoulder deep in Cray and SGI supercomputers without
worrying about it. Then the day came where I needed to do surgery on my
network analyzer. I figured the $20 for the coating was cheap insurance. I
don't have $37k sitting around to replace it should I fry it. That was the
first time I ever put on a wrist strap too!
-Bob
On Mon, Jan 25, 2010 at 11:27 AM, Charles P. Steinmetz <
charles_steinmetz@lavabit.com> wrote:
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges
when
handling modern semiconductors. Would it make sense to spray the
Masonite
with a weak copper sulphate or similar solution so as to make the
masonite
slightly conductive, but not so conductive that 155 VAC connections could
not
safely rest upon it? Is there a better-suited material that could be
used
to replace the Masonite?
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try to
keep the RH in my house under 45% -- it is generally 20% or less in the
winter). I've been fooling with static-sensitive parts for 35 years and
haven't lost one to static yet. With that perspective, my preferred
benchtop is white Formica with a very, very slightly pebbled surface. Very
durable, including to molten solder, and small parts show up well. I use
rubberized "gunsmith" mats for preventing scratches to delicate workpieces
(these happen to be anti-static, but that is not why I have them).
Other bench thoughts:
Bench depth is very important. I sometimes work on equipment that is more
than 24" deep, so I want at least 30" of clear space in front of any
obstructions (power strips, Variac, test equipment, whatever). In the past,
I used a "flying bridge" over the rear 18" of a 48"-deep bench to elevate
the test equipment, which worked very well. Now I use 24" deep adjustable
wire-rack shelving units behind a 30" benchtop (As others have pointed out,
you can do the same with equipment racks -- I'm not a fan of rack-mounting
test equipment unless the racks are anchored and everything is on slides,
which I was not prepared to do). I don't have enough shop real estate to
have a permanent access aisle behind the test equipment, so the bench and
racks have large (5") locking polyurethane wheels and can be pulled out
relatively easily for reconfiguration. This provides plenty of stability
for electronic projects, but you wouldn't want to mount a big vise on the
bench and try to bend 1" rebar. For that, I have a separate metalworking
shop.
Bench height is also important. I prefer a tall bench, suited to working
standing or sitting on an ergonomic stool, so my bench top is 44" above the
floor -- a bit below my standing elbow height.
Finally, one can never have too many power outlets, or too much light, in a
workshop. Lighting should be arranged so that it doesn't cause specular
reflections from the workpiece or the faces of test equipment.
Best regards,
Charles
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of Charles P. Steinmetz
Sent: Monday, January 25, 2010 10:27 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
One generally looks for static-dissipative surfaces, rather than conductive surfaces. 1 Megohm/square, for instance. The idea is to keep everything isopotential as charge drops onto things, not to rigorously establish a common voltage.
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet
You haven't lost one that you know of. It also depends on the kinds of parts you're working with. There are some that are quite sensitive AND which don't fail outright, but just degrade performance a bit when they take a hit. It also depends on the energy behind the hit, of course. An example might be the MiniCircuits ERA-4 or ERA-5 (just because I happen to have the data sheet handy). Take a look at the later pages in the report, and you can see where the gain changes slightly as a result of 100V ESD hits (see page 6, where you can see gain dropping about 1.5 dB over 8 pulses, with about 0.1dB per hit.)
As they say at the end of the report:
The new amplifier ERA-4XSM shows gradual degradation in the gain and the
device voltage. That fact is not so bad. Even with the multiple stress a customer
would rather have gradual changes then catastrophic failure. The amplifier
withstands a single 100V ESD pulse, or 3 pulses at 50V.
http://www.minicircuits.com/pages/pdfs/an60028.pdf
When we (JPL) do site visits to vendors, lackadaisical approaches to ESD handling are one of the common problems. For us, who are building just one or two of something that's going to be going somewhere where repair isn't an option, latent damage and gradual degradation are a big deal.
It's really a "habit" thing that everyone has to get used to. That's why even nuts and bolts come in ESD packaging (even though they're obviously ESD immune): it gets people in the mindset of "come in the area, put on the wrist strap". Back in the 70s, when ESD processes started to be used, they would have multiple categories of parts, some which needed ESD precautions (CMOS parts, DRAMs,etc.) and some which didn't (resistors, capacitors). It was found that workers would be working with something in one category, and the habits would carry over to the others, so the industry, in general, went to the "everything is ESD sensitive" approach.
The worst offenders for ESD are the engineers (like those of us reading the list!), because they actually know what parts are sensitive and which aren't, and tend to take shortcuts with the non-sensitive parts. Which works, sort of, until they guess wrong, and cook something. "Hey, why is the NF on this LNA 0.2 dB higher than it was yesterday?"
jim
I've still got a paper copy of an HP Bench Brief from 1983 that was one
of my first introductions to the dangers of ESD. I've used a wrist
strap and antistatic mat since then. ESD protection in the ICs has
improved since then, but I think that the article is still mostly
applicable today.
http://www.hparchive.com/Bench_Briefs/HP-Bench-Briefs-1983-03-05.pdf
Ed
Lux, Jim (337C) wrote:
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of Charles P. Steinmetz
Sent: Monday, January 25, 2010 10:27 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
One generally looks for static-dissipative surfaces, rather than conductive surfaces. 1 Megohm/square, for instance. The idea is to keep everything isopotential as charge drops onto things, not to rigorously establish a common voltage.
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet
You haven't lost one that you know of. It also depends on the kinds of parts you're working with. There are some that are quite sensitive AND which don't fail outright, but just degrade performance a bit when they take a hit. It also depends on the energy behind the hit, of course. An example might be the MiniCircuits ERA-4 or ERA-5 (just because I happen to have the data sheet handy). Take a look at the later pages in the report, and you can see where the gain changes slightly as a result of 100V ESD hits (see page 6, where you can see gain dropping about 1.5 dB over 8 pulses, with about 0.1dB per hit.)
As they say at the end of the report:
The new amplifier ERA-4XSM shows gradual degradation in the gain and the
device voltage. That fact is not so bad. Even with the multiple stress a customer
would rather have gradual changes then catastrophic failure. The amplifier
withstands a single 100V ESD pulse, or 3 pulses at 50V.
http://www.minicircuits.com/pages/pdfs/an60028.pdf
When we (JPL) do site visits to vendors, lackadaisical approaches to ESD handling are one of the common problems. For us, who are building just one or two of something that's going to be going somewhere where repair isn't an option, latent damage and gradual degradation are a big deal.
It's really a "habit" thing that everyone has to get used to. That's why even nuts and bolts come in ESD packaging (even though they're obviously ESD immune): it gets people in the mindset of "come in the area, put on the wrist strap". Back in the 70s, when ESD processes started to be used, they would have multiple categories of parts, some which needed ESD precautions (CMOS parts, DRAMs,etc.) and some which didn't (resistors, capacitors). It was found that workers would be working with something in one category, and the habits would carry over to the others, so the industry, in general, went to the "everything is ESD sensitive" approach.
The worst offenders for ESD are the engineers (like those of us reading the list!), because they actually know what parts are sensitive and which aren't, and tend to take shortcuts with the non-sensitive parts. Which works, sort of, until they guess wrong, and cook something. "Hey, why is the NF on this LNA 0.2 dB higher than it was yesterday?"
jim
So looking at ESD mat material at Digikey, there appears to be a
bewildering array of choices. Elastomer, rubber, vinyl,
thermoplastic, laminate, foam rubber, and polyethelene.
Any guidelines about what to choose?
Scott
On Jan 25, 2010, at 11:59 AM, Ed Palmer ed_palmer@sasktel.net wrote:
I've still got a paper copy of an HP Bench Brief from 1983 that was
one of my first introductions to the dangers of ESD. I've used a
wrist strap and antistatic mat since then. ESD protection in the
ICs has improved since then, but I think that the article is still
mostly applicable today.
http://www.hparchive.com/Bench_Briefs/HP-Bench-Briefs-1983-03-05.pdf
Ed
Lux, Jim (337C) wrote:
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-
bounces@febo.com] On Behalf Of Charles P. Steinmetz
Sent: Monday, January 25, 2010 10:27 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset
in
avoiding short circuits, etc., I am concerned about static
discharges when
handling modern semiconductors. Would it make sense to spray
the Masonite
with a weak copper sulphate or similar solution so as to make
the masonite
slightly conductive, but not so conductive that 155 VAC
connections
could not
safely rest upon it? Is there a better-suited material that
could be used
to replace the Masonite?
One generally looks for static-dissipative surfaces, rather than
conductive surfaces. 1 Megohm/square, for instance. The idea is to
keep everything isopotential as charge drops onto things, not to
rigorously establish a common voltage.
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I
try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for
35
years and haven't lost one to static yet
You haven't lost one that you know of. It also depends on the
kinds of parts you're working with. There are some that are quite
sensitive AND which don't fail outright, but just degrade
performance a bit when they take a hit. It also depends on the
energy behind the hit, of course. An example might be the
MiniCircuits ERA-4 or ERA-5 (just because I happen to have the data
sheet handy). Take a look at the later pages in the report, and
you can see where the gain changes slightly as a result of 100V ESD
hits (see page 6, where you can see gain dropping about 1.5 dB over
8 pulses, with about 0.1dB per hit.)
As they say at the end of the report:
The new amplifier ERA-4XSM shows gradual degradation in the gain
and the
device voltage. That fact is not so bad. Even with the multiple
stress a customer
would rather have gradual changes then catastrophic failure. The
amplifier
withstands a single 100V ESD pulse, or 3 pulses at 50V.
http://www.minicircuits.com/pages/pdfs/an60028.pdf
When we (JPL) do site visits to vendors, lackadaisical approaches
to ESD handling are one of the common problems. For us, who are
building just one or two of something that's going to be going
somewhere where repair isn't an option, latent damage and gradual
degradation are a big deal.
It's really a "habit" thing that everyone has to get used to.
That's why even nuts and bolts come in ESD packaging (even though
they're obviously ESD immune): it gets people in the mindset of
"come in the area, put on the wrist strap". Back in the 70s, when
ESD processes started to be used, they would have multiple
categories of parts, some which needed ESD precautions (CMOS parts,
DRAMs,etc.) and some which didn't (resistors, capacitors). It was
found that workers would be working with something in one category,
and the habits would carry over to the others, so the industry, in
general, went to the "everything is ESD sensitive" approach.
The worst offenders for ESD are the engineers (like those of us
reading the list!), because they actually know what parts are
sensitive and which aren't, and tend to take shortcuts with the non-
sensitive parts. Which works, sort of, until they guess wrong, and
cook something. "Hey, why is the NF on this LNA 0.2 dB higher than
it was yesterday?"
jim
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
My first job was in a blasting cap plant in 1960. There were
military devices so sensitive they could be set off by turning
on a nearby fluorescent desk lamp.
I learned that the human body has a capacitance of 400 pico F.
Getting up from a chair could raise a couple of kilovolts. We
walked on conductive rubber floors wearing conductive rubber
shoes. Bench tops were conductive rubber. Nobody had thought of
the wrist strap yet.
In those days, rubber was made conductive with carbon black. It
was almost as effective as a pencil at marking things. If the
anti-static material is not black, maybe it won't be a marking
hazard.
A megohm and 400 pF has a time constant of 400 microseconds, but
you do get the kilovolt spike. The wrist strap looks really good
as long as your motion is the only source of static electricity.
It keeps your body from ever reaching kilovolt potentials.
Bill Hawkins
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Scott Burris
Sent: Monday, January 25, 2010 2:11 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Conducting Bench Top Material
So looking at ESD mat material at Digikey, there appears to be a
bewildering array of choices. Elastomer, rubber, vinyl,
thermoplastic, laminate, foam rubber, and polyethelene.
Any guidelines about what to choose?
Scott
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of Bill Hawkins
I learned that the human body has a capacitance of 400 pico F.
Getting up from a chair could raise a couple of kilovolts. We
walked on conductive rubber floors wearing conductive rubber
shoes. Bench tops were conductive rubber. Nobody had thought of
the wrist strap yet.
If you're in and out of ESD areas, then shoes with conductive soles are easier to use than always wrist strapping. Ditto if you're working on something big where the cord for the wrist strap gets in the way. In some of our clean rooms, we have booties to go over your street shoes that have conductive coatings on them, and a conductive ribbon that you tuck into your sock to make contact. (And you go stand on a test pad to make sure, of course).
I like the conductive shoes approach, it's pretty screw up proof, because you don't have to remember to plug your wrist strap in when you come to the bench, but the floor needs to be conductive, too.
In those days, rubber was made conductive with carbon black. It
was almost as effective as a pencil at marking things. If the
anti-static material is not black, maybe it won't be a marking
hazard.
These days, the black bins are dissipative and not marking. The black foam is history (we all have ICs with corroded leads in the garage where the black foam turns to goo). Here at JPl, we don't use the pink bags/peanuts/stuff at all, because apparently, the coating can flake or rub off. We use plastic that has a very thin metalized layer, and I think that's pretty much industry standard now.
A megohm and 400 pF has a time constant of 400 microseconds, but
you do get the kilovolt spike. The wrist strap looks really good
as long as your motion is the only source of static electricity.
It keeps your body from ever reaching kilovolt potentials.
And the megohm is important to keep you from inadvertently dying when you happen to accidentally contact the AC line.
Natural materials like wood, cotton, wool and even concrete have an
equilibrium
water content that changes with ambient relative humidity. This makes
these materials
conductive but not conductive enough to carry dangerous currents.
They are still good insulators
for mains voltage.
The textiles can change moisture content and conductivity quite
quickly
as they have fibre diameters of about 20 microns or so, but even at
20% RH static charges
dissipate in seconds. Plastics, however, tend to be very non-
conductive and charges
can be held for hours. Also, some plastics form electrets which stay
"charged" even under water.
A great insight to the static electricity problem came from articles
I read as a young boy in old (1910)
articles such as "make yourself an electrophorous" in popular science
mags.
A can lid was filled with melted resin. When solid it was rubbed with
wool. A metal
disk with insulated handle was placed on the resin and grounded with
a finger.
The disk was then lifted off the resin and would be found to have a
high charge (and voltage) on it.
(half inch fat spark to ground)
This process of induced charging and potential multiplication is the
danger on work benches.
The main way to overcome it is to have an isopotential environment
which naturally occurs with
natural materials where all charges rapidly drain away. Wood is good,
it does not produce charge
when rubbed and rapidly drains any charge away. And unless soaking
wet it will not electrocute you
if you are leaning on it when you touch and active power lead. (my
theory from experience is that
it is the ground that would kill you when if you were electrocuted.
If you have good soles on your shoes
and the other hand in your pocket an accidental touch to high voltage
is survivable)
just a few thoughts,
Neville Michie
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/
time-nuts
and follow the instructions there.
Bill Hawkins wrote:
My first job was in a blasting cap plant in 1960. There were
military devices so sensitive they could be set off by turning
on a nearby fluorescent desk lamp.
I learned that the human body has a capacitance of 400 pico F.
Getting up from a chair could raise a couple of kilovolts. We
walked on conductive rubber floors wearing conductive rubber
shoes. Bench tops were conductive rubber. Nobody had thought of
the wrist strap yet.
In those days, rubber was made conductive with carbon black. It
was almost as effective as a pencil at marking things. If the
anti-static material is not black, maybe it won't be a marking
hazard.
A megohm and 400 pF has a time constant of 400 microseconds, but
you do get the kilovolt spike. The wrist strap looks really good
as long as your motion is the only source of static electricity.
It keeps your body from ever reaching kilovolt potentials.
Your finger and hand makes a 700ps to 1 ns risetime device. Slew-rate
wise you can be up in several milions of V/us. The arm has sufficient
induction that it takes a considerable time before the body discharges,
but the hand creats the leader and then the big blow comes from the body
discharge. Just as a cloud and a ligthning bolt, but in man-size.
However, being ESD aware does not mean going maniac about it. It's more
like don't finger on things which is very hot. You need to build good
habits to avoid doing something bad.
Cheers,
Magnus
Lux, Jim (337C) wrote:
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of Bill Hawkins
I learned that the human body has a capacitance of 400 pico F.
Getting up from a chair could raise a couple of kilovolts. We
walked on conductive rubber floors wearing conductive rubber
shoes. Bench tops were conductive rubber. Nobody had thought of
the wrist strap yet.
If you're in and out of ESD areas, then shoes with conductive soles are easier to use than always wrist strapping. Ditto if you're working on something big where the cord for the wrist strap gets in the way. In some of our clean rooms, we have booties to go over your street shoes that have conductive coatings on them, and a conductive ribbon that you tuck into your sock to make contact. (And you go stand on a test pad to make sure, of course).
I like the conductive shoes approach, it's pretty screw up proof, because you don't have to remember to plug your wrist strap in when you come to the bench, but the floor needs to be conductive, too.
The first greeting a new collueage gets when comming first day to work
is "What shoesize are you?". We order ESD shoes for more or less
everyone. Our US sales-people is known to ask if it is real Birkenstock
shoes. :)
In those days, rubber was made conductive with carbon black. It
was almost as effective as a pencil at marking things. If the
anti-static material is not black, maybe it won't be a marking
hazard.
These days, the black bins are dissipative and not marking. The black foam is history (we all have ICs with corroded leads in the garage where the black foam turns to goo). Here at JPl, we don't use the pink bags/peanuts/stuff at all, because apparently, the coating can flake or rub off. We use plastic that has a very thin metalized layer, and I think that's pretty much industry standard now.
This is why you guys don't have a pink-day at the office! :)
You got to have a silly pink-day every once in a while just for the fun
of it. I'll see if not the HW department can adapt it, as they have
tried non-casual-friday (usual dress code is... um... casual).
A megohm and 400 pF has a time constant of 400 microseconds, but
you do get the kilovolt spike. The wrist strap looks really good
as long as your motion is the only source of static electricity.
It keeps your body from ever reaching kilovolt potentials.
And the megohm is important to keep you from inadvertently dying when you happen to accidentally contact the AC line.
There is a reason for EKG equipment being measured for isolation
properties. The medical staff wants to select the time and dosage of
larger currents through the heart, and preference is towards patients
that badly need it.
Cheers,
Magnus
Back about 1981, we had piles of 6502s, etc and decide to some "antistatic testing". We put a 40pin ZIF socket into a VIC-20, and then set about trying to fry the uP using carpet, a cat, car seats, etc. The DUT was then put back into the VIC and series of tests run to verify operation. I don't think we ever had a failure. Of course, there may have been some hiding that we missed, but all the static damage I've seen has been pretty severe.
That said, I always use a wrist strap and mat if I'm working on something I don't want to break further.
-Dave
----- Original Message -----
From: "Charles P. Steinmetz" charles_steinmetz@lavabit.com
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Monday, January 25, 2010 11:27:11 AM GMT -07:00 US/Canada Mountain
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet. With that perspective, my
preferred benchtop is white Formica with a very, very slightly
pebbled surface. Very durable, including to molten solder, and small
parts show up well. I use rubberized "gunsmith" mats for preventing
scratches to delicate workpieces (these happen to be anti-static, but
that is not why I have them).
Other bench thoughts:
Bench depth is very important. I sometimes work on equipment that is
more than 24" deep, so I want at least 30" of clear space in front of
any obstructions (power strips, Variac, test equipment,
whatever). In the past, I used a "flying bridge" over the rear 18"
of a 48"-deep bench to elevate the test equipment, which worked very
well. Now I use 24" deep adjustable wire-rack shelving units behind
a 30" benchtop (As others have pointed out, you can do the same with
equipment racks -- I'm not a fan of rack-mounting test equipment
unless the racks are anchored and everything is on slides, which I
was not prepared to do). I don't have enough shop real estate to
have a permanent access aisle behind the test equipment, so the bench
and racks have large (5") locking polyurethane wheels and can be
pulled out relatively easily for reconfiguration. This provides
plenty of stability for electronic projects, but you wouldn't want to
mount a big vise on the bench and try to bend 1" rebar. For that, I
have a separate metalworking shop.
Bench height is also important. I prefer a tall bench, suited to
working standing or sitting on an ergonomic stool, so my bench top is
44" above the floor -- a bit below my standing elbow height.
Finally, one can never have too many power outlets, or too much
light, in a workshop. Lighting should be arranged so that it doesn't
cause specular reflections from the workpiece or the faces of test equipment.
Best regards,
Charles
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
Hi
If you are manually loading up a wire bonder with conventional CMOS chips, ESD damage is a very real thing. You can haul the chip over to a SEM and actually take pictures of he craters you blast in it. Very cool pictures. No cat's, carpets, or Windhurst machines needed. Just normal operators with missing wrist straps will do the trick quite nicely.
Bob
On Jan 26, 2010, at 2:21 AM, d.seiter@comcast.net wrote:
Back about 1981, we had piles of 6502s, etc and decide to some "antistatic testing". We put a 40pin ZIF socket into a VIC-20, and then set about trying to fry the uP using carpet, a cat, car seats, etc. The DUT was then put back into the VIC and series of tests run to verify operation. I don't think we ever had a failure. Of course, there may have been some hiding that we missed, but all the static damage I've seen has been pretty severe.
That said, I always use a wrist strap and mat if I'm working on something I don't want to break further.
-Dave
----- Original Message -----
From: "Charles P. Steinmetz" charles_steinmetz@lavabit.com
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Monday, January 25, 2010 11:27:11 AM GMT -07:00 US/Canada Mountain
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet. With that perspective, my
preferred benchtop is white Formica with a very, very slightly
pebbled surface. Very durable, including to molten solder, and small
parts show up well. I use rubberized "gunsmith" mats for preventing
scratches to delicate workpieces (these happen to be anti-static, but
that is not why I have them).
Other bench thoughts:
Bench depth is very important. I sometimes work on equipment that is
more than 24" deep, so I want at least 30" of clear space in front of
any obstructions (power strips, Variac, test equipment,
whatever). In the past, I used a "flying bridge" over the rear 18"
of a 48"-deep bench to elevate the test equipment, which worked very
well. Now I use 24" deep adjustable wire-rack shelving units behind
a 30" benchtop (As others have pointed out, you can do the same with
equipment racks -- I'm not a fan of rack-mounting test equipment
unless the racks are anchored and everything is on slides, which I
was not prepared to do). I don't have enough shop real estate to
have a permanent access aisle behind the test equipment, so the bench
and racks have large (5") locking polyurethane wheels and can be
pulled out relatively easily for reconfiguration. This provides
plenty of stability for electronic projects, but you wouldn't want to
mount a big vise on the bench and try to bend 1" rebar. For that, I
have a separate metalworking shop.
Bench height is also important. I prefer a tall bench, suited to
working standing or sitting on an ergonomic stool, so my bench top is
44" above the floor -- a bit below my standing elbow height.
Finally, one can never have too many power outlets, or too much
light, in a workshop. Lighting should be arranged so that it doesn't
cause specular reflections from the workpiece or the faces of test equipment.
Best regards,
Charles
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and follow the instructions there.
I am concerned about static discharges when
handling modern semiconductors.
These days it's not just semiconductors at risk given the tiny geometry of
passives. At work we had a work station where we assembled a board with
all passive components, so no thought was given to ESD control. We traced
a series of mysterious failures to ESD affecting the value of some
resistors. Now ESD control is just about everywhere!
-Joe Fitzgerald KM1P
Everything old is new again.
The 25+ year old HP Bench Brief that I referred to a few messages back
warns about that.
Ed
Joe Fitzgerald wrote:
I am concerned about static discharges when
handling modern semiconductors.
These days it's not just semiconductors at risk given the tiny geometry of
passives. At work we had a work station where we assembled a board with
all passive components, so no thought was given to ESD control. We traced
a series of mysterious failures to ESD affecting the value of some
resistors. Now ESD control is just about everywhere!
-Joe Fitzgerald KM1P
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
Ed Palmer wrote:
Everything old is new again.
The 25+ year old HP Bench Brief that I referred to a few messages back
warns about that.
"Nothing usefull could be found in old documents, they just didn't have
the same technology as we have, and hence not the problems." Well, not
that much different. Scale is the main thing. People have been studying
all kinds of things, so good clues may still lay around if you dare look
for them.
Thanks for remembering this stuff.
Cheers,
Magnus
Hi
If you are manually loading up a wire bonder with conventional CMOS chips, ESD damage is a very real thing. You can haul the chip over to a SEM and actually take pictures of he craters you blast in it. Very cool pictures. No cat's, carpets, or Windhurst machines needed. Just normal operators with missing wrist straps will do the trick quite nicely.
Bob
On Jan 26, 2010, at 2:21 AM, d.seiter@comcast.net wrote:
Back about 1981, we had piles of 6502s, etc and decide to some "antistatic testing". We put a 40pin ZIF socket into a VIC-20, and then set about trying to fry the uP using carpet, a cat, car seats, etc. The DUT was then put back into the VIC and series of tests run to verify operation. I don't think we ever had a failure. Of course, there may have been some hiding that we missed, but all the static damage I've seen has been pretty severe.
That said, I always use a wrist strap and mat if I'm working on something I don't want to break further.
-Dave
----- Original Message -----
From: "Charles P. Steinmetz" charles_steinmetz@lavabit.com
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Monday, January 25, 2010 11:27:11 AM GMT -07:00 US/Canada Mountain
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet. With that perspective, my
preferred benchtop is white Formica with a very, very slightly
pebbled surface. Very durable, including to molten solder, and small
parts show up well. I use rubberized "gunsmith" mats for preventing
scratches to delicate workpieces (these happen to be anti-static, but
that is not why I have them).
Other bench thoughts:
Bench depth is very important. I sometimes work on equipment that is
more than 24" deep, so I want at least 30" of clear space in front of
any obstructions (power strips, Variac, test equipment,
whatever). In the past, I used a "flying bridge" over the rear 18"
of a 48"-deep bench to elevate the test equipment, which worked very
well. Now I use 24" deep adjustable wire-rack shelving units behind
a 30" benchtop (As others have pointed out, you can do the same with
equipment racks -- I'm not a fan of rack-mounting test equipment
unless the racks are anchored and everything is on slides, which I
was not prepared to do). I don't have enough shop real estate to
have a permanent access aisle behind the test equipment, so the bench
and racks have large (5") locking polyurethane wheels and can be
pulled out relatively easily for reconfiguration. This provides
plenty of stability for electronic projects, but you wouldn't want to
mount a big vise on the bench and try to bend 1" rebar. For that, I
have a separate metalworking shop.
Bench height is also important. I prefer a tall bench, suited to
working standing or sitting on an ergonomic stool, so my bench top is
44" above the floor -- a bit below my standing elbow height.
Finally, one can never have too many power outlets, or too much
light, in a workshop. Lighting should be arranged so that it doesn't
cause specular reflections from the workpiece or the faces of test equipment.
Best regards,
Charles
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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--
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
Steve wrote.
Wasn't life so much easier with valves (tubes)...
Amen brother.
Regards.
Max. K 4 O D S.
Email: max@maxsmusicplace.com
Transistor site http://www.funwithtransistors.net
Vacuum tube site: http://www.funwithtubes.net
Music site: http://www.maxsmusicplace.com
To subscribe to the fun with transistors group send an email to.
funwithtransistors-subscribe@yahoogroups.com
To subscribe to the fun with tubes group send an email to,
funwithtubes-subscribe@yahoogroups.com
----- Original Message -----
From: "Steve Rooke" sar10538@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Wednesday, January 27, 2010 8:23 PM
Subject: Re: [time-nuts] Conducting Bench Top Material
Wasn't life so much easier with valves (tubes)...
:-)
Steve
2010/1/27 Bob Camp lists@cq.nu:
Hi
If you are manually loading up a wire bonder with conventional CMOS chips,
ESD damage is a very real thing. You can haul the chip over to a SEM and
actually take pictures of he craters you blast in it. Very cool pictures.
No cat's, carpets, or Windhurst machines needed. Just normal operators
with missing wrist straps will do the trick quite nicely.
Bob
On Jan 26, 2010, at 2:21 AM, d.seiter@comcast.net wrote:
Back about 1981, we had piles of 6502s, etc and decide to some
"antistatic testing". We put a 40pin ZIF socket into a VIC-20, and then
set about trying to fry the uP using carpet, a cat, car seats, etc. The
DUT was then put back into the VIC and series of tests run to verify
operation. I don't think we ever had a failure. Of course, there may have
been some hiding that we missed, but all the static damage I've seen has
been pretty severe.
That said, I always use a wrist strap and mat if I'm working on something
I don't want to break further.
-Dave
----- Original Message -----
From: "Charles P. Steinmetz" charles_steinmetz@lavabit.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Monday, January 25, 2010 11:27:11 AM GMT -07:00 US/Canada Mountain
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges
when
handling modern semiconductors. Would it make sense to spray the
Masonite
with a weak copper sulphate or similar solution so as to make the
masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be
used
to replace the Masonite?
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet. With that perspective, my
preferred benchtop is white Formica with a very, very slightly
pebbled surface. Very durable, including to molten solder, and small
parts show up well. I use rubberized "gunsmith" mats for preventing
scratches to delicate workpieces (these happen to be anti-static, but
that is not why I have them).
Other bench thoughts:
Bench depth is very important. I sometimes work on equipment that is
more than 24" deep, so I want at least 30" of clear space in front of
any obstructions (power strips, Variac, test equipment,
whatever). In the past, I used a "flying bridge" over the rear 18"
of a 48"-deep bench to elevate the test equipment, which worked very
well. Now I use 24" deep adjustable wire-rack shelving units behind
a 30" benchtop (As others have pointed out, you can do the same with
equipment racks -- I'm not a fan of rack-mounting test equipment
unless the racks are anchored and everything is on slides, which I
was not prepared to do). I don't have enough shop real estate to
have a permanent access aisle behind the test equipment, so the bench
and racks have large (5") locking polyurethane wheels and can be
pulled out relatively easily for reconfiguration. This provides
plenty of stability for electronic projects, but you wouldn't want to
mount a big vise on the bench and try to bend 1" rebar. For that, I
have a separate metalworking shop.
Bench height is also important. I prefer a tall bench, suited to
working standing or sitting on an ergonomic stool, so my bench top is
44" above the floor -- a bit below my standing elbow height.
Finally, one can never have too many power outlets, or too much
light, in a workshop. Lighting should be arranged so that it doesn't
cause specular reflections from the workpiece or the faces of test
equipment.
Best regards,
Charles
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
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To unsubscribe, go to
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To unsubscribe, go to
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--
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
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19:36:00
Steve Rooke wrote:
Wasn't life so much easier with valves (tubes)...
Nostalgia?
Valves (tubes) warmer in close proximity, yes. Global warming should
make that, on average, less helpful.
In the 60's listening to rock music, I could look at the final tubes in
a dark room and see the purple glow inside dance with the music.
Anyone else?
Solid state amps just can't do that. Way cool. I never tried it with
cannabis, but probably even better.
Other than that memory, and certain trade-offs at big Rf power, I'll say
I no longer encourage the glowing bulbs for most things.
And at least I can drop a transistor on the floor without too much damage ;-)
Robert G8RPI.
--- On Thu, 28/1/10, Rex rexa@sonic.net wrote:
From: Rex rexa@sonic.net
Subject: Re: [time-nuts] Conducting Bench Top Material
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Date: Thursday, 28 January, 2010, 5:50
Steve Rooke wrote:
Wasn't life so much easier with valves (tubes)...
Nostalgia?
Valves (tubes) warmer in close proximity, yes. Global warming should make that, on average, less helpful.
In the 60's listening to rock music, I could look at the final tubes in a dark room and see the purple glow inside dance with the music.
Anyone else?
Solid state amps just can't do that. Way cool. I never tried it with cannabis, but probably even better.
Other than that memory, and certain trade-offs at big Rf power, I'll say I no longer encourage the glowing bulbs for most things.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
And no-one ever invented complimentary N channel and P channel valves
(tubes).
And they had a service life of 5000 hours and they stoppd working
properly.
On 28/01/2010, at 6:51 PM, Robert Atkinson wrote:
And at least I can drop a transistor on the floor without too much
damage ;-)
Robert G8RPI.
--- On Thu, 28/1/10, Rex rexa@sonic.net wrote:
From: Rex rexa@sonic.net
Subject: Re: [time-nuts] Conducting Bench Top Material
To: "Discussion of precise time and frequency measurement" <time-
nuts@febo.com>
Date: Thursday, 28 January, 2010, 5:50
Steve Rooke wrote:
Wasn't life so much easier with valves (tubes)...
Nostalgia?
Valves (tubes) warmer in close proximity, yes. Global warming
should make that, on average, less helpful.
In the 60's listening to rock music, I could look at the final
tubes in a dark room and see the purple glow inside dance with the
music.
Anyone else?
Solid state amps just can't do that. Way cool. I never tried it
with cannabis, but probably even better.
Other than that memory, and certain trade-offs at big Rf power,
I'll say I no longer encourage the glowing bulbs for most things.
time-nuts mailing list -- time-nuts@febo.com
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time-nuts
and follow the instructions there.
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time-nuts
and follow the instructions there.
Warning: Way OT
When the vacuum tube was born, there were half as many people on
this planet, and global climate change wasn't a problem. Very few
people will talk about populution. It's as if there was a blind
spot in the brain. Maybe there's no intelligent life in the
Universe because all life evolves with similar selection pressures.
Once technology removes natural predators (or stops world wars with
the atomic bomb), population heads for the sky until the big die-off.
If other people don't have a problem with having four kids, I have
no problem with using vacuum tubes and Edison bulbs.
All in my humble opinion, of course.
Bill Hawkins
-----Original Message-----
From: Rex
Sent: Wednesday, January 27, 2010 11:50 PM
Steve Rooke wrote:
Wasn't life so much easier with valves (tubes)...
Nostalgia?
Valves (tubes) warmer in close proximity, yes. Global warming should
make that, on average, less helpful.
........
glowing bulbs
Other than that memory, and certain trade-offs at big Rf power, I'll say
I no longer encourage the glowing bulbs for most things.
In message 924780D899C84029950F3D9CAEE28054@cyrus, "Bill Hawkins" writes:
When the vacuum tube was born, there were half as many people on
this planet, and global climate change wasn't a problem. Very few
people will talk about populution. It's as if there was a blind
spot in the brain.
No, the blind spot is making a big issue out of population control
in countries where the environmental footprint per person is virtually
nill essential zero, in order to obscure the fact that approx 1% of
the population of the planet is responsible for 99.99% of our
problems, environmental or otherwise.
Poul-Henning
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Hi
If we ever go back to tubes we're going to have a bunch of tech's knocked out on the floor. Nobody has a clue about high voltage any more. You had to have a good respect for it on a tube circuit or you got in big trouble.
Bob
On Jan 27, 2010, at 9:23 PM, Steve Rooke wrote:
Hi
If you are manually loading up a wire bonder with conventional CMOS chips, ESD damage is a very real thing. You can haul the chip over to a SEM and actually take pictures of he craters you blast in it. Very cool pictures. No cat's, carpets, or Windhurst machines needed. Just normal operators with missing wrist straps will do the trick quite nicely.
Bob
On Jan 26, 2010, at 2:21 AM, d.seiter@comcast.net wrote:
Back about 1981, we had piles of 6502s, etc and decide to some "antistatic testing". We put a 40pin ZIF socket into a VIC-20, and then set about trying to fry the uP using carpet, a cat, car seats, etc. The DUT was then put back into the VIC and series of tests run to verify operation. I don't think we ever had a failure. Of course, there may have been some hiding that we missed, but all the static damage I've seen has been pretty severe.
That said, I always use a wrist strap and mat if I'm working on something I don't want to break further.
-Dave
----- Original Message -----
From: "Charles P. Steinmetz" charles_steinmetz@lavabit.com
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Monday, January 25, 2010 11:27:11 AM GMT -07:00 US/Canada Mountain
Subject: Re: [time-nuts] Conducting Bench Top Material
Bruce wrote:
Although over the years the non-conductive top has been an asset in
avoiding short circuits, etc., I am concerned about static discharges when
handling modern semiconductors. Would it make sense to spray the Masonite
with a weak copper sulphate or similar solution so as to make the masonite
slightly conductive, but not so conductive that 155 VAC connections
could not
safely rest upon it? Is there a better-suited material that could be used
to replace the Masonite?
I notice that many folks who have contributed on this thread use
anti-static benchtops, but I have never found it necessary (and I try
to keep the RH in my house under 45% -- it is generally 20% or less
in the winter). I've been fooling with static-sensitive parts for 35
years and haven't lost one to static yet. With that perspective, my
preferred benchtop is white Formica with a very, very slightly
pebbled surface. Very durable, including to molten solder, and small
parts show up well. I use rubberized "gunsmith" mats for preventing
scratches to delicate workpieces (these happen to be anti-static, but
that is not why I have them).
Other bench thoughts:
Bench depth is very important. I sometimes work on equipment that is
more than 24" deep, so I want at least 30" of clear space in front of
any obstructions (power strips, Variac, test equipment,
whatever). In the past, I used a "flying bridge" over the rear 18"
of a 48"-deep bench to elevate the test equipment, which worked very
well. Now I use 24" deep adjustable wire-rack shelving units behind
a 30" benchtop (As others have pointed out, you can do the same with
equipment racks -- I'm not a fan of rack-mounting test equipment
unless the racks are anchored and everything is on slides, which I
was not prepared to do). I don't have enough shop real estate to
have a permanent access aisle behind the test equipment, so the bench
and racks have large (5") locking polyurethane wheels and can be
pulled out relatively easily for reconfiguration. This provides
plenty of stability for electronic projects, but you wouldn't want to
mount a big vise on the bench and try to bend 1" rebar. For that, I
have a separate metalworking shop.
Bench height is also important. I prefer a tall bench, suited to
working standing or sitting on an ergonomic stool, so my bench top is
44" above the floor -- a bit below my standing elbow height.
Finally, one can never have too many power outlets, or too much
light, in a workshop. Lighting should be arranged so that it doesn't
cause specular reflections from the workpiece or the faces of test equipment.
Best regards,
Charles
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
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2010/1/28 Bill Hawkins bill@iaxs.net:
Warning: Way OT
When the vacuum tube was born, there were half as many people on
this planet, and global climate change wasn't a problem. Very few
people will talk about populution. It's as if there was a blind
spot in the brain. Maybe there's no intelligent life in the
Universe because all life evolves with similar selection pressures.
Once technology removes natural predators (or stops world wars with
the atomic bomb), population heads for the sky until the big die-off.
If other people don't have a problem with having four kids, I have
no problem with using vacuum tubes and Edison bulbs.
All in my humble opinion, of course.
True, but I can never recall having a problem with ESD with them
(which was the current topic of the thread).
Steve
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
2010/1/28 Rex rexa@sonic.net:
Steve Rooke wrote:
Wasn't life so much easier with valves (tubes)...
Nostalgia?
Nostalgia ain't what it used to be!
Valves (tubes) warmer in close proximity, yes. Global warming should make
that, on average, less helpful.
And we heated our houses less.
In the 60's listening to rock music, I could look at the final tubes in a
dark room and see the purple glow inside dance with the music.
Anyone else?
Way, way back I was listening in the background to an old Teak amp one
day when I thought that it sounded a bit distorted. Went over to look
at the chassis and saw one of the valves in the output stage with it's
anode glowing red! Hmmm, seems it was conducting just a little more
than it was supposed to do due to a biasing component failure. A
couple of minutes later and some work with a soldering iron and the
sound was fine again. That chassis went on forever on that same valve.
Solid state amps just can't do that. Way cool. I never tried it with
cannabis, but probably even better.
They soon go legs up if you apply too much voltage or current which
valves would just shrug off.
Other than that memory, and certain trade-offs at big Rf power, I'll say I
no longer encourage the glowing bulbs for most things.
They certainly still held their own in high power RF stages but I
wouldn't go out of my way to build something out of them now.
As for conductive surfaces for benches and the like, RS Components
used to sell a static conducting matting by the square yard that you
could order. It was a yellow and about 1/8" thick flexible dense
rubberized material. We covered our benches and floor around our
workplaces and had the press-stud fittings riveted to them so you
could clip your earthing strap to it. It was very hard waring and
coped well with molten solder dripping onto it. I believe I still have
a sheet of it somewhere in the garage.
73
Steve
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
2010/1/28 Neville Michie namichie@gmail.com:
And no-one ever invented complimentary N channel and P channel valves
(tubes).
True but they did come up with a lot of designs involving multiple
grids etc which allowed a single valve to perform more complex
functions. Remember the old magic-eye indicators, triodes and pentodes
in the same envelope, mixers, etc.
And they had a service life of 5000 hours and they stoppd working properly.
And they were easy to fault-find, and replacement was a breeze.
I'm too far off topic now, sorry to hi-jack the thread.
Steve
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
2010/1/29 Bob Camp lists@cq.nu:
If we ever go back to tubes we're going to have a bunch of tech's knocked out on the floor. Nobody has a clue about high voltage any more. You had to have a good respect for it on a tube circuit or you got in big trouble.
Remember the valves that used to have the grid at the top of the
envelope via a separate connection. That made it real easy to inject a
signal for tracing through the circuit, you just put your finger on it
and listened for mains hum at the speaker, for instance. hat was
alright till you found the valve that had an anode at the top...
That's going back a looong way.
Steve
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.