Are mains surge protectors needed in the UK?

[half_pint]

No, we're talking about a voltage surge.

Voltage never causes device failure,

There will be no current unless something conducts.
Brilliant!!!


I.E. If there were no devices plugged in (or wired in) the only effect
would be a voltage spike on the interior power lines, but no current flow
per see (besides leakage).

And no current flow = no damage.

If, however, a susceptible device is connected to the power line and the
voltage spike is sufficient to cause electrical breakdown then the device
fails and may pull excessive current as a result of the failure, which, if
severe enough, will blow the fuse. But the failure has already occurred by
the time the fuse sees anything, much less blows.

Only current flow causes damage, current flow blows fuses.
A main spike hits the robust components of the PSU first
these are not sensitive to high voltages, infact the voltages inside
them are dangerous to humans,

No, it isn't.
voltage.

An obvious contradiction, as stated.

Rubbish that is how they are designed to work!!

A zener conducts when the voltage across it reaches a certain level,
otherwise is does not conduct, and the source better be current limited,
most commonly by a series resistor, or else the zener will self destruct.
In that case, by over heating.

Ans of course they are always current limited by a series resirtor in
appliances.

Not hardly.

I am afraid it is.

'Melting' has nothing to do with it.
What?


No offense but you really don't understand semi-conductors at all.

You are maing no sense ar all.

No one ever said they were 'surplus'. The problem is you don't understand
the nature of electronics and the purpose of various protection devices.

I do

A fuse blows on a sustained current fault and breaks the connection: a
preferable situation to continuing to draw fault current because, for one,
it prevents fires.

That has nothing to do with 'protecting' what is already a damaged device
causing the current fault.

You don't really understand electricity do you?

You're never going to understand it till you get it out of your head that
'excessive current' is the only thing that damages semi-conductors.

Heat is the only souce of damage, and current not voltage
produces heat.

Surely you jest.

Why in the word do you think power supplies, much less multi-voltage units,
even exist if electronics works 'quite happily' at just any old voltage?

I think you missed the point.

Just plain wrong.

Really now, even your own decryption, as misguided as it is, contradicts
THAT absurdity because, if it were true, there would never ever be an
electronic failure, unless someone shoved it inside a 900F oven. And that
is clearly not the case.

You don't have to heat the whole device, the damage is usually localised

No, it isn't. And I'd advise you to go learn something about
semi-conductors before you make such statements because they make it rather
obvious you have no idea how they work.

I have every idea how they work, much more so than you.

I'm posting from alt.comp.hardware.pc-homebuilt.



And you think that 'proves' what?

My point and my arguement, unsurprisingly.

Oh, really? And what were you doing with the case to these devices open so
that you were getting a 'static discharge' from the 'ICs'?

Still a huge voltage surge and no anti - surge device yet MIRACULOUSLY
ALL THOSE SENSITIVE DEVICES WERE TOTALLY UNDAMAGED
HOW STRANGE????????

But since you bring it up you could expand your horizons by doing a web
search on ICs and static electricity and, in particular, ESD protection.

Already have, not that I needed to, everything I found bacjed my
case.

Here's one to get you started:
http://www.informit.com/articles/article.asp?p=21704&seqNum=3

"In general, MOS devices are sensitive to voltage spikes and
static-electricity discharges. This can cause many problems when you have
to replace MOS devices, especially complementary-symmetry metal-oxide
semiconductor (CMOS) devices. The level of static electricity on your body
is high enough to destroy the inputs of a CMOS device if you touch its pins
with your fingers."

Basically irrelevant garbage, i could handle a million circuit board
without
causing any damage. A case of a little knowledge incorrectly applied.

Which you think 'proves' what?

My point.

Have fun.

I will

 

[half_pint]

And they are completely different. Silicon is an element, and silicone
is a synthetic polymer compound. Therefore, saying that semiconductors
use silicone is rubbish.

Thats why I never said that of course, except in a typo
I used silicone to illustrate the high metling point of silicon
based products. You try using both words a lot with out making
the samne typos.

 

[w_tom]

Minimally acceptable 'whole house' protector sold for
residential service are about 1000 joules and 50,000 amps.
Protectors with higher ratings are also sold. Johnathan's
post about an MOV at only 1500 A is made completely irrelevant
by existing retail products. But it is good to see that
Johnathan still wants to argue about rubbish.

Furthermore most every plug-in protector does not use Gas
Discharge Tubes (GDTs) They are too expensive. Since many
plug-in protectors are only sold to increase manufacturer's
profits (another reason why they are grossly undersized), then
installing those expensive GDTs would be counterproductive.
Again we reference some expensive plug-in protectors in the
scary pictures:
http://www.zerosurge.com/HTML/movs.html
Even the more expensive plug-in surge protectors have no
GDTs. Again Johnathan posts what he hopes rather than what
really exists.

 

[half_pint]

"Johannes H Andersen" <[email protected]>
wrote in message

"Johannes H Andersen" <[email protected]>
wrote in message

half_pint wrote:

[...]

As said before, voltages also kills semiconductor devices. Why do you
think there are such things as electrostatic bags?

To protect semiconductors from static electricity as opposed to
mains electricity.

LOL! How much do you know about electricity?

I have forgotten far more than you will ever know.

Too bad your memory is like a sieve. You might have heard about electric
potential? Measured in Volt in both static and mains cases. A semiconductor
such as a transistor must have the atoms organised in a particular way,
that result in energy bands the for controlled movements of charges through
the lattice. The electrons are not free as in metals or carbon, if that was
the case then the electrons would be able to move equally in all directions
and the semiconductor would not do its job.

If you now increase the electric potential over the designed value, then
these delicate structures and the energy bands breaks down. This is not
the same thing as burning a fuse.

They are not delicate structures, no more than a grain of sand is delicate.
A zener diode, works by 'breaking down'. however it is not damaged
permanently it still will work as a normal diode with in its limits. there
is no permanent change in its functionality.

And nothing breaks down anyway it is normal operation at such vooltages.

 

[VWWall]

w_tom wrote:

You owe us a response re 14 AWG wire.

Furthermore most every plug-in protector does not use Gas
Discharge Tubes (GDTs) They are too expensive. Since many
plug-in protectors are only sold to increase manufacturer's
profits (another reason why they are grossly undersized), then
installing those expensive GDTs would be counterproductive.
Again we reference some expensive plug-in protectors in the
scary pictures:
http://www.zerosurge.com/HTML/movs.html
Even the more expensive plug-in surge protectors have no
GDTs. Again Johnathan posts what he hopes rather than what
really exists.

I wonder what GD1 in this drawing is?

http://www.apuk04.dsl.pipex.com/w_tom_is_a_wanker/cct.jpg

Virg Wall

 

[Johannes H Andersen]

"Johannes H Andersen" <[email protected]>
wrote in message

[...]

As said before, voltages also kills semiconductor devices. Why do you
think there are such things as electrostatic bags?

To protect semiconductors from static electricity as opposed to
mains electricity.

LOL! How much do you know about electricity?

I have forgotten far more than you will ever know.

Too bad your memory is like a sieve. You might have heard about electric
potential? Measured in Volt in both static and mains cases. A semiconductor
such as a transistor must have the atoms organised in a particular way,
that result in energy bands the for controlled movements of charges through
the lattice. The electrons are not free as in metals or carbon, if that was
the case then the electrons would be able to move equally in all directions
and the semiconductor would not do its job.

If you now increase the electric potential over the designed value, then
these delicate structures and the energy bands breaks down. This is not
the same thing as burning a fuse.

 

[w_tom]

All this from the same Jonathan Buzzard who claimed that
wire inductance in a British ring main was sufficient to
create destructive surges. This is the same physic major who
could not even say what that wire inductance was or put
numbers to the resulting surge. Wondered how long you would
take to arrive. Instead, why don't you please explain to the
group how power wires inside British walls can create
destructive transients when power is switched? I am still
waiting for that scientific marvel. Still waiting even for
your numbers for massive wire inductance created by those
British rings.

Good to see you still invent science, misrepresent what I
post, and have some religious belief that underground
wires cannot carry destructive surges. The world has not
changed.

Previously, when Jonathan posted some myth about surges not
existing on underground wires, he was confronted with this
application note from Polyphaser - an industry benchmark:
http://www.polyphaser.com/datasheets/PTD1028.pdf

Lightning strikes somewhere across the street close to
the below grade West cable vault. ... The first line
of defense is the telco protection panel, but the panel
must be connected to a low resistance / inductance
ground. There was no adequate ground available in the
telephone room.

And so surge damage created; incoming on the buried wire
from the west cable vault. "How can this be", declares
Jonathan Buzzard. "I said buried wires need not be surge
protected." Again, we have this small problem called reality.

So please, Jonathan. Fill us with your wisdom. Tell us how
inductance in those wires of a British ring main create
destructive surges? I am still waiting for those numbers and
your peer reviewed paper.

 

[Mike Tomlinson]

Furthermore most every plug-in protector does not use Gas
Discharge Tubes (GDTs) They are too expensive.

Really?
Please explain what device GD1 in this circuit is, then:
http://jasper.org.uk/w_tom/cct.jpg

Here's a photo of the device itself, to prove it doesn't just exist on
paper. I am using three in this room at the moment. They cost me ukp4
each: http://jasper.org.uk/w_tom/surge.jpg

This protector also protects against common mode surges, something you
claim plug-in protectors cannot do (see the diagram if you don't believe
me.)

I note you have studiously avoided answering my question about whether
you are employed by, or have an interest in, the manufacturers of the
whole house protectors you constantly advocate. I therefore conclude
your so-called "advice" is biased and partial.

Finally, I have spent some time today on google.groups reading threads
in which you participate. In almost every one you come off worse. Why
do you think this is? Has it ever occurred to you that you may be
wrong?

 

[Mike Tomlinson]

misrepresent what I
post,

That's rich coming from you, who twisted a comment from me about the
earthing system at our Canary Islands site into saying that I was
willing to accept lightning damage. I am still waiting for your
apology.

I am still waiting for those numbers and
your peer reviewed paper.

Where is /your/ peer reviewed paper? (Don't bother: we all know you
don't have one.)

Where is your answer to my questions about the surge protector circuit
diagram I posted?

Where is your answer to my question about whether you are employed by,
or have a financial interest in, the makers of whole house surge
protection devices? Time to come clean and declare your interest.

 

[David Maynard]

No because the metalic contacts have evapourated.
Replace the contacts and it would be fine.

<chuckle>

 

[Johannes H Andersen]

"Johannes H Andersen" <[email protected]>
wrote in message

"Johannes H Andersen" <[email protected]>
wrote in message


half_pint wrote:

[...]

As said before, voltages also kills semiconductor devices. Why do you
think there are such things as electrostatic bags?

To protect semiconductors from static electricity as opposed to
mains electricity.

LOL! How much do you know about electricity?

I have forgotten far more than you will ever know.

Too bad your memory is like a sieve. You might have heard about electric
potential? Measured in Volt in both static and mains cases. A semiconductor
such as a transistor must have the atoms organised in a particular way,
that result in energy bands the for controlled movements of charges through
the lattice. The electrons are not free as in metals or carbon, if that was
the case then the electrons would be able to move equally in all directions
and the semiconductor would not do its job.

If you now increase the electric potential over the designed value, then
these delicate structures and the energy bands breaks down. This is not
the same thing as burning a fuse.

They are not delicate structures, no more than a grain of sand is delicate.

What are you on about warp_saint?

A grain of sand is made of the the same raw material, but it's not a
transistor! Transistor silicon is carefully grown into an almost fault free
lattice. Impurity elements are then carefully inserted to establish the
energy bands. That way P and N materials are created.

A zener diode, works by 'breaking down'. however it is not damaged
permanently it still will work as a normal diode with in its limits. there
is no permanent change in its functionality.

A zener diode is designed with a Zener knee Voltage for the desired effect.
however the Zeener knee is inside the designed Voltage range. If you exceed
the designed Voltage, you blow the Zener diode for much the same reasons
that you'll blow a transistor. If you ever have experimented with electronics,
you'll have come across many duff transistors etc with no physical sign of
burns whatsoever, just dead because you have used the wrong voltage or used
the wrong polarity.

 

[w_tom]

Elsewhere in this topic is a claim that fuses can prevent
surge damage. First put numbers to the claim. Surges
accomplish damage in microseconds. Fuses, circuit breakers,
and thermal links take milliseconds to open. How, is a fuse
suppose to stop what has already occurred well into the past?
It does not. Surges do not blow fuses. However fuses blow as
a result of damage created by the surge.

Mike previously posted:

Many good quality European surge protectors illuminate a
warning lamp to indicate when the protective devices have
degraded such that they are no longer effective and that the
protector should be replaced.

So we ask the MOV professionals to define "degraded". From
a Littelfuse application note AN9310:

A failed device is defined by a ±10% change in the
nominal varistor voltage at the 1mA point. This does
not imply a non-protecting device, but rather a device
whose clamping voltage has been slightly altered.

This is called "degraded". The threshold or let-through
voltage of 330 volts (as printed as required on surge
protectors boxes) changes to under 300 volts or over 360
volts. Protector will still work, but it has degraded and is
considered by manufacturer datasheets as failed.

Another and catastrophic failure mode is vaporization. This
is the totally unacceptable event when the MOV is grossly
undersized - operates beyond what manufacturer designed.

Again from Littelfuse application note AN9772:

Varistors initially fail in a short-circuit mode when
subjected to surges beyond their peak current/energy
ratings. They also short-circuit when operated at
steady-state voltages well beyond their voltage ratings.
This latter mode of stress may result in the eventual
open-circuiting of the device due to melting of the
lead solder joint. When the device fails in the shorted
mode ... a large amount of energy can be introduced,
causing mechanical rupture of the package accompanied by
expulsion of package material in both solid and gaseous
forms [also called vaporization] . Steps may be taken
to minimize this potential hazard by the following
techniques: 1) fusing the varistor to limit high fault
currents, ...

To meet the human safety requirements imposed by UL1449 2nd
edition, manufacturers install a thermal link as demonstrated
in a schematic from Mike Tomlinson. When does that thermal
link open? When the MOV is degraded? Of course not. The
thermal link only blows open when an MOV was so grossly
undersized as to short circuit and vaporized. Thermal link
blows when MOV operates well beyond what manufacturer
intended. This thermal link for human safety is necessary to
meet UL1449 2nd edition.

How can this be? Mike Tomlinson told us that surge
protectors:

... illuminate a warning lamp to indicate when the
protective devices have degraded ...

He even provided a schematic to show us the thermal link that
blows when MOV degrades!

A 330 volt MOV degraded so that it operates at 300 volts or
360 volts will blow the thermal fuse? Of course not. One
first has to believe Mike Tomlinson has been educated. As
demonstrated in a scary picture from Zerosurge, the MOVs can
even be removed and the indicator lamp says protector works
"OK":
http://www.zerosurge.com/HTML/movs.html
But then those MOVs did not fail catastrophically - blow the
thermal link. Indication lamp is to report catastrophic
failure.

For those who want to learn what that indicator light
reports: "OK" light can only report when surge protector was
so grossly undersized as to vaporize MOVs - the unacceptable
catastrophic failure in AN9772 and the reason why UL (an
organization dedicated to human safety) created UL1449 2nd
edition. So that a vaporizing MOV does not result in fire and
death, UL1449 requires that a catastrophically failing MOV not
threaten human life. Indicator lamp indicates that an
essential human safety fuse - a thermal link - has blown. It
indicates that the surge protector was grossly undersized as
to even blow its thermal link.

The normal failure mode for MOVs is defined by AN9310. A
degraded MOV will not blow any fuse because it does not short
circuit and vaporize. To blow the fuse, an MOV must become a
short to AC mains voltage for milliseconds. Aa degraded MOV
will not open (blow) the thermal disconnect device LK1. But a
catastrophically failed (short circuited) MOV will.

An MOV does not get hotter only because its let-through
voltage changes; is below 300 volts or above 360 volts. Lets
remember those numbers posted up to. Surges are microsecond
events. If they damage the MOV, then milliseconds of AC
electric cause the thermal link to fail. But a grossly
undersized MOV short circuits. Milliseconds later, AC
electric heats that damaged MOV, pushes too much current to
blow that thermal link, and illuminates that warning light
LP1.

That warning light will report a catastrophically failed
surge protector but can not report that a protector has
degraded. Light will report one type of failure and cannot
report a good surge protector.

A surge protector is only as effective as its earth ground.
Facts that don't change no matter what fancy lights report and
no matter how Mike Tomlinson insults others.

 

[w_tom]

Why would I apologize to someone whose very first post to me
was to call me a twat? Why would I apologize to someone who
posts insults every time he is exposed as technically naive?
Why would I apologize to someone who cannot even admit to the
problem of high impedance down 18 meters of safety ground wire
- who instead ignores numbers he cannot contest (because he
does not understand wire impedance)? Why would I apologize to
someone so foolish as to claim a "degraded" MOV causes thermal
links to blow? I never apologize to those who are so superior
and so technically naive as to insult what they cannot
challenge. But Mike Tomlinson owes the newsgroups an apology
for insulting others rather than posting technical facts.

You have lightning damage on your Canary Island site
typically because the protection system is defective. What
did AT&T do in the early days of ESS-1 - the first electronic
switching stations - when lightning caused damage to those
first electronics switches? They found and fixed defects in
the earth ground system. They did as others in this
discussion did to solve repeated surge damage. They fixed the
ground.

You are suffering damage in the Canary Islands and know so
much as to claim you don't have an earthing problem? We even
have testimony from others who fixed electronic damage by
correcting the earth ground system. We have numerous quotes
from industry professionals who tell you, up front, that the
solution to such surge damage begins with the earthing
system. However you had a contractor install an earthing
system and still had damage? Therefore earthing is not a
solution? No wonder you need someone to insult. It does not
work when you insult your Canary Island station. It does not
cure the problem when others also tried to tell you same.

How pathetic are you? So intolerant as to even complain
about top posting. And now you want an apology? Apologize to
yourself. You are the one insulting others. Your latest
insult:

You're a gormless ****wit

Can we assume you have an emotional instability - or that you
are again providing technical facts to support your myths.
You want me to apologize for your brain and how it posts?
Please return to the real world.

Mike Tomlinson is even willing to accept surge damage on the
Canary Islands. Only a defeatist would accept such damage.
Protection from CG strikes is that well proven as to be
routine even where lightning strikes 40 times per year. Mike
Tomlinson would rather insult than fix his defective earthing
system. These are the same people who claim a plug-in
protectors will protect electronics? He must be right. His
vocabulary of insults is clearly much larger than mine. And
his ability to misrepresent is superb.

 

[w_tom]

With basic knowledge of earthing, then you knew that every
floor on the EMB is, essentially, earth grounded. But then
you knew that from the last time we had this discussion. Did
you forget?

Please tell us how switching power off a British ring main
with so much 'inductance in wires' causes a massive surge? I
am still waiting for that science miracle to be explained. I
am still waiting for your numbers on that wire inductance and
the resulting surge.

Protection from the most lightning prone locations is
routine and well understood. Others who have been in Mike's
Canary Island situation say "no problem":
http://www.telebyteusa.com/primer/ch6.htm
See Section 6.4: WHEN SHOULD YOU WORRY ABOUT LIGHTNING?

Conceptually, lightning protection devices are switches to
ground. Once a threatening surge is detected, a lightning
protection device grounds the incoming signal connection
point of the equipment being protected. Thus, redirecting
the threatening surge on a path-of-least resistance
(impedance) to ground where it is absorbed.
Any lightning protection device must be composed of two
"subsystems," a switch which is essentially some type of
switching circuitry and a good ground connection-to allow
dissipation of the surge energy.

It defines both the single point earth ground and a
connection to that ground - surge protectors or hardwire.
Curious. They did exactly what I have demonstrated.

http://www.harvardrepeater.org/news/lightning.html

Well I assert, from personal and broadcast experience
spanning 30 years, that you can design a system that
will handle *direct lightning strikes* on a routine
basis. It takes some planning and careful layout, but
it's not hard, nor is it overly expensive. At WXIA-TV,
my other job, we take direct lightning strikes nearly
every time there's a thunderstorm. Our downtime from
such strikes is almost non-existant. The last time we
went down from a strike, it was due to a strike on the
power company's lines knocking *them* out, ...
Since my disasterous strike, I've been campaigning
vigorously to educate amateurs that you *can* avoid
damage from direct strikes. The belief that there's
no protection from direct strike damage is *myth*. ...
The keys to effective lightning protection are
surprisingly simple, and surprisingly less than
obvious. Of course you *must* have a single point
ground system that eliminates all ground loops. And
you must present a low *impedance* path for the energy
to go. That's most generally a low *inductance* path
rather than just a low ohm DC path.
http://lists.contesting.com/_towertalk/1997-April/004413.html
The basic scenario is to install a Single Point Ground

System that is installed at the building entry. It shunts

everything to ground before it goes in the building. If
you can keep it outside, then you don't really have to do
much inside. IMO disconnecting the cables is more
psychological than preventive.
http://scott-inc.com/html/ufer.htm
The land owner warned us that this tower was frequently
struck, and equipment had been repeatedly damaged despite
increased precautions. Indeed, during July construction,
the masonry workers left the site after "a bolt sent
fireballs rolling down the [existing] tower". With a
sensitive CMOS controlled transmitter and a talking remote
control selected for the installation, I knew that any
transient overvoltage protection devices I would specify
would need a very conductive path to ground to divert
strike energy away from the equipment. ...
In sixteen months, the site has maintained twenty-four hour
per day operation with ZERO downtime except due to AC power
failure. With equipment so susceptible to transients, this
kind of performance is unusual in this region, especially
on this hill.

Mike would have us believe that an inferior US electrical
distribution system creates surge damage in the US. He
forgets that the UK has almost no lightning compared to the US
and still suffered significant damage. Especially true was
the amount of modem damage in the UK during an unusual
thunderstorm on 4 July 2004. Trivial storm by American
standards. Numerous UK modems were unnecessarily damaged due
to no properly earthed protectors.

Plug-in protectors in the US are three wire. Makes no
difference. A distance of much more than 3 meters (10 feet)
to earth ground means the plug-in protector is not earthed -
as demonstrated by previously posted numbers that remain
unchallenged. Excessive wire impedance from wall receptacle
to earth ground explains why plug-in protectors are so
ineffective, why the manufacturer does not even claim to
protect from the destructive type of surge, and why Mike
Tomlinson assumes a certain amount of surge damage is
acceptable. To maintain a myth about plug-in protection, he
must ignore the numbers. How then does he deal with testimony
from industry professionals who have learned concepts of
effective protection and don't suffer damage.

How does he
explain 25 direct strikes per year to electronics atop the
Empire State Building without damage? A surge protector is
only as effective as its earth ground.

You tell me w_tom, because according to your previous
statements, you can only get effective earthing if you
have a ground earth that is less tan three metres in
length. Last time I checked the top of the Empire States
Building was considerably more than three metres from
the ground. Therefore going by what you say there is no
way on earth to get effective surge protection.

As effective surge protection can be achieved on top of
the ESB then you are clearly talking rubbish. However we
already knew this.

 

[David Maynard]

Voltage never causes device failure,

Research it and learn, or remain ignorant. Your choice.

And no current flow = no damage.

Research electrostatic breakdown in semiconductors.

Only current flow causes damage,
false.

current flow blows fuses.
true

A main spike hits the robust components of the PSU first

I suppose you want to ignore modem lines.

these are not sensitive to high voltages,

Depends on how high the voltage.

infact the voltages inside
them are dangerous to humans,

Some are; others aren't.

The fact of the matter is that you know nothing of which you speak.

Rubbish that is how they are designed to work!!

There cannot be "whatever the input voltage" to the one and only device in
your statement, the zener, if it's "the same."

Ans of course they are always current limited by a series resirtor in
appliances.

Well, no. That just happens to be the cheapest and most common means when
they're used as a simple voltage reference. It is not the only way they're
used.

I am afraid it is.

You apparently haven't a clue.

It's like saying silicone is 'essentially sand', and has the properties of
sand. Or that glass is 'essentially sand', and has the properties of sand.

One has to go back to before even the days of alchemy to find such
absurdities promulgated as 'knowledge'.

What?

Simple enough statement.

You are maing no sense ar all.

That's probably how a medieval alchemist would feel about a discussion on
quantum mechanics, and for the same reason.

I do

It is obvious you don't and what's further obvious is that you refuse to
learn a thing about it.

You don't really understand electricity do you?

I have already provided you with corroborating authoritative sources for my
explanations.

I challenge you to provide one for your absurd contention that voltage
cannot damage semiconductors.

Heat is the only souce of damage, and current not voltage
produces heat.

Wrong, and I've provided authoritative sources to corroborate it.

I think you missed the point.

If you thought so that certainly doesn't elaborate, but don't bother as
I've had enough of your absurdities anyway.

You don't have to heat the whole device, the damage is usually localised

You actually stumbled onto something that's halfway correct: you can have
localized heating. It's not, however, very relevant to the point because
the thermal conductivity of semiconductors won't allow so dramatic a
difference, when compared to your claimed '900F' destruction point, as to
matter to the illustration. So we need fools shoving them into 700F ovens,
instead of 900F ovens, before any device would ever fail. It is still an
absurdity.

Btw, the melting point of silicon isn't 900F, it's (much) higher, but I'm
using your numbers to illustrate that even your own 'theory' is irrational.

I have every idea how they work, much more so than you.

Feel free to quote a text book, or some other authoritative source, that
supports your fantasies.

My point and my arguement, unsurprisingly.

Since you made no 'point' there is nothing it could.

Still a huge voltage surge and no anti - surge device yet MIRACULOUSLY
ALL THOSE SENSITIVE DEVICES WERE TOTALLY UNDAMAGED
HOW STRANGE????????

Not at all. It has nothing to do with ICs being 'immune' from static
voltage damage but it's obviously useless to attempt educating you about
anything.

Already have, not that I needed to, everything I found bacjed my
case.
ROTFLMAO



Basically irrelevant garbage, i could handle a million circuit board
without
causing any damage.

I can too. It isn't 'fingers', it's whether your body has built up an
electrostatic charge and then you touch one.

Semiconductors, nowadays, also include protective devices inside them to
reduce the chances of ESD damage. that doesn't mean they're 'immune' from
it and it still proves the point of voltage causing damage.

A case of a little knowledge incorrectly applied.

An excellent description of yourself.

My point.

Which would be what?

I will

Didn't find anything, did ya? <chuckle>

 

[David Maynard]

"Johannes H Andersen" <[email protected]>
wrote in message

"Johannes H Andersen" <[email protected]>
wrote in message


half_pint wrote:

[...]

As said before, voltages also kills semiconductor devices. Why do

you

think there are such things as electrostatic bags?

To protect semiconductors from static electricity as opposed to
mains electricity.

LOL! How much do you know about electricity?

I have forgotten far more than you will ever know.

Too bad your memory is like a sieve. You might have heard about electric
potential? Measured in Volt in both static and mains cases. A
semiconductor

such as a transistor must have the atoms organised in a particular way,
that result in energy bands the for controlled movements of charges
through

the lattice. The electrons are not free as in metals or carbon, if that
was

the case then the electrons would be able to move equally in all
directions

and the semiconductor would not do its job.

If you now increase the electric potential over the designed value, then
these delicate structures and the energy bands breaks down. This is not
the same thing as burning a fuse.

They are not delicate structures, no more than a grain of sand is delicate.

Got that bit of information from a voo-doo doll, no doubt.

A zener diode, works by 'breaking down'. however it is not damaged

In a previous post you made a comment about 'a little knowledge incorrectly
applied' and that is a beautiful example.

permanently it still will work as a normal diode with in its limits. there
is no permanent change in its functionality.

And nothing breaks down anyway it is normal operation at such vooltages.

MOSFET gate breakdown is not recoverable.

http://www.americanmicrosemi.com/tutorials/mosfets.htm

"breakdown voltage in MOS devices do not depend upon p-n junction stress
but rather upon the thickness and quality of the insulating oxide. When
breakdown does occur, the oxide is punctured and the device is destroyed."

 

[VWWall]

Top posted for w_tom:

See below:

What are you on about warp_saint?

A suggestion: Let's leave this thread to half_wit and w_tom. The rest
of us can read it for laughs!

Virg Wall

 

[David Maynard]

"Johannes H Andersen" <[email protected]>
wrote in message

half_pint wrote:

"Johannes H Andersen" <[email protected]>
wrote in message


half_pint wrote:

[...]

As said before, voltages also kills semiconductor devices. Why do
you

think there are such things as electrostatic bags?

To protect semiconductors from static electricity as opposed to
mains electricity.

LOL! How much do you know about electricity?

I have forgotten far more than you will ever know.

Too bad your memory is like a sieve. You might have heard about electric
potential? Measured in Volt in both static and mains cases. A
semiconductor

such as a transistor must have the atoms organised in a particular way,
that result in energy bands the for controlled movements of charges
through

the lattice. The electrons are not free as in metals or carbon, if that
was

the case then the electrons would be able to move equally in all
directions

and the semiconductor would not do its job.

If you now increase the electric potential over the designed value, then
these delicate structures and the energy bands breaks down. This is not
the same thing as burning a fuse.

They are not delicate structures, no more than a grain of sand is delicate.

What are you on about warp_saint?

A grain of sand is made of the the same raw material, but it's not a
transistor! Transistor silicon is carefully grown into an almost fault free
lattice. Impurity elements are then carefully inserted to establish the
energy bands. That way P and N materials are created.

A zener diode, works by 'breaking down'. however it is not damaged
permanently it still will work as a normal diode with in its limits. there
is no permanent change in its functionality.

A zener diode is designed with a Zener knee Voltage for the desired effect.
however the Zeener knee is inside the designed Voltage range. If you exceed
the designed Voltage, you blow the Zener diode for much the same reasons
that you'll blow a transistor. If you ever have experimented with electronics,
you'll have come across many duff transistors etc with no physical sign of
burns whatsoever, just dead because you have used the wrong voltage or used
the wrong polarity.

In the case of junction semiconductor devices the failure mode is most
commonly current heating of the junction and the problem with too much
voltage, in those case, is it causes excess current to flow. Same, but
worse, for reverse voltage as junctions that shouldn't conduct do, and vice
versa, which scrambles what the circuit is designed for (bias points are
nonsensical, current flows where it wasn't supposed to, etc.), causing
excessive junction currents and, hence, temperature.

'Electronics', as a generic term, is complex and composed of many device
type and process. And there are many different failure mechanisms,
depending on what kind of devices are being used.

Even the generic term "transistor" doesn't clarify whether it's a bipolar
junction transistor, or a "Field Effect Transistor" (FET), or MOSFET, or
another.

http://www.semiconfareast.com/fmechs_die.html

Even that article doesn't cover everything.

MOSFETs, which are sensitive destructive breakdown from excessive voltage,
are the most common device technology used in PCs.

An amusing story about the first days of FET transistor production
illustrates the problem. Before they realized just how vulnerable the
devices were the failure rates were astronomical, in every sense of the
word. Some PCB manufacturers could get a single board with the things on
them to work. ALL had failures.

The problem was the devices had no static protection in them and things
like conductive foam/tube carriers hadn't been though of yet (what for,
eh?). They typically came 'plugged' into a block of plain old styrofoam
and, as it turned out, the simple act of pulling them back off created
enough static electricity to destroy them.

One manufacturer, before the 'secret' was fleshed out, got so fed up with
the 'out of box' unreliability (100% board failure) that they decided to
pre test the FETs before insertion. So they constructed a device test bed
and sat a fellow down to check them one by one.

The procedure ended up being: pull device from foam block, insert into test
fixture, observe device is bad, throw device away." Not a single one
passed! (for the now obvious reason)

That test ended up being instrumental in finding the problem, however, as
the device manufacturer, in response to these 'claims' of failure (sure
pal), had already implemented a "100% device test" (so it can't be)...
before inserting them into the foam block, of course.

 

[Jonathan Buzzard]

All this from the same Jonathan Buzzard who claimed that
wire inductance in a British ring main was sufficient to
create destructive surges.

It is, and I still maintain that it is. However if you want I can run
through the surge created as the magnetic field collapses in a 100W light
bulb as it is turned on. Lots and lots of precise measurements including
the coil dimensions of the bulb filament. We can then look at the discharge
required to destroy a CMOS junction. The first is at least an order of
magnitude greater than the second. I have not turned it into an HTML page
yet, but the calculations have been done just to rub your stupid nose in
the fact that you are wrong wrong wrong.

This is the same physic major who
could not even say what that wire inductance was or put
numbers to the resulting surge.

I did indeed put numbers to the resultant surge, anyone is welcome to
Google for them.

Wondered how long you would
take to arrive. Instead, why don't you please explain to the
group how power wires inside British walls can create
destructive transients when power is switched? I am still
waiting for that scientific marvel. Still waiting even for
your numbers for massive wire inductance created by those
British rings.

Got a better one in bulb filaments Think about it for a bit w_tom. A
nice air coil that has an instantaneous current flowing when it blows of
hundreds of amps (remember the filament is cold). Happens all the time,
and perhaps you can explain why when a bulb blows it usually trips the MCB?
Then again you don't believe in back EMF.

Good to see you still invent science, misrepresent what I
post, and have some religious belief that underground
wires cannot carry destructive surges. The world has not
changed.

Previously, when Jonathan posted some myth about surges not
existing on underground wires, he was confronted with this
application note from Polyphaser - an industry benchmark:
http://www.polyphaser.com/datasheets/PTD1028.pdf

And so surge damage created; incoming on the buried wire
from the west cable vault. "How can this be", declares
Jonathan Buzzard. "I said buried wires need not be surge
protected." Again, we have this small problem called reality.

It is all to do with raised ground potentials and there is a good chance
that no amount of surge protection is going to help with that sort of
local strike.

So please, Jonathan. Fill us with your wisdom. Tell us how
inductance in those wires of a British ring main create
destructive surges? I am still waiting for those numbers and
your peer reviewed paper.

I am working on it, taking a standard 100W bulb, because then my figures
will be beyond question.

JAB.

 

[Jonathan Buzzard]

Minimally acceptable 'whole house' protector sold for
residential service are about 1000 joules and 50,000 amps.
Protectors with higher ratings are also sold. Johnathan's
post about an MOV at only 1500 A is made completely irrelevant
by existing retail products. But it is good to see that
Johnathan still wants to argue about rubbish.

You might spell my name correctly. Only people with ignorant parents
have Jonathan spelt with two h's.

As for the rating of MOV's just get a copy of the RS catalogue and read it.

Furthermore most every plug-in protector does not use Gas
Discharge Tubes (GDTs) They are too expensive.

Absolute rubbish, they can be had retail for around 2GBP in quantities of
one.

Since many
plug-in protectors are only sold to increase manufacturer's
profits (another reason why they are grossly undersized), then
installing those expensive GDTs would be counterproductive.
Again we reference some expensive plug-in protectors in the
scary pictures:
http://www.zerosurge.com/HTML/movs.html
Even the more expensive plug-in surge protectors have no
GDTs. Again Johnathan posts what he hopes rather than what
really exists.

Yes they do if they want to meet the British Standard.


JAB.