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The model for SW appears to missing.
If anyone can help me create a .model
statement for schematic. That would be great.
I could not figure out how to do it from
the help file alone.

Thanks,

//Michael

--- In LTspice@..., "michaelstuarts" <michaelstuarts@...> wrote:

The model for SW appears to missing.
If anyone can help me create a .model
statement for schematic. That would be great.
I could not figure out how to do it from
the help file alone.

Thanks,

//Michael

Hello Michael,

From the Help:

S1 out 0 in 0 MySwitch
.model MySwitch SW(Ron=.1 Roff=1Meg Vt=0 Vh=-.5 Lser=10n Vser=.6)

You don't say what your switch will be used for, but I'm betting that if you deleted the last three terms in the model above, it would do what you wanted.

If you're having trouble relating that to your schematic, do this:
1. Place a sw from the parts chooser, and change its value to MySwitch.
2. Add a SPICE directive, and paste in the .model text.

If you're trying to control it from something like TTL or CMOS, change Vt to 1.8V, or something between the logic levels.

Regards,
Tony

--- In LTspice@..., Michael Stuarts wrote:

The model for SW appears to missing. If anyone can help me create
a .model statement for schematic that would be great. I could not
figure out how to do it from the help file alone.

Why not? Do you have a reading comprehension problem? This is a
serious question because Help both clearly explains that you must
provide a model statement to define your switch and gives you a
link to an example schematic that you may run if you are too
unfamiliar with the correlation between the netlist notation
example provided and how it derives from the schematic.

Perhaps English is not your native language? Or perhaps you really
didn't read Help? I am curious because I really would like to
understand why Help (which seems perfectly fine to me) does not
seem to work for so many users (so there is no wrong answer on
your part other than a less than honest one).

Regards -- analogspiceman

PS: Here is the relevant section from Help.
-----------------------------------------------------------
S. Voltage Controlled Switch

Symbol Names: SW

Syntax: Sxxx n1 n2 nc+ nc- <model> [on,off]

Example:

S1 out 0 in 0 MySwitch

.model MySwitch SW(Ron=.1 Roff=1Meg Vt=0 Vh=-.5 Lser=10n Vser=.6)

The voltage between nodes nc+ and nc- controls the switch's
impedance between nodes n1 and n2. A model card is required
to define the behavior of the switch. See the schematic file
.&#92;examples&#92;Educational&#92;Vswitch.asc to see an example of a model
card placed directly on a schematic as a SPICE directive.
-----------------------------------------------------------

--- In LTspice@..., "analogspiceman" <analogspiceman@...> wrote:

--- In LTspice@..., Michael Stuarts wrote:

The model for SW appears to missing. If anyone can help me
create a .model statement for schematic that would be great.
I could not figure out how to do it from the help file alone.

Why not? Do you have a reading comprehension problem?

Hello analogspiceman and all others,

We shouldn't attack users when we don't know about their
knowledge and capabilities. Please keep that in mind.

Best regards,
Helmut
Moderator

PS:
Especially using the switch sw is often the first time
where a new user has to define a model.

Indeed, we should attack users, who attack users - it seems that this
is the only language, those pseudo-masters will understand.

Johannes Herrmann / Yahoo Micbuilders Group

P.S. In our group, such an incident is unthinkable. that'll be worth a
strike.

best regards...

I think a distinction needs to be made between attacking the issue and
attacking the user..
Cheers
AG

In message <4E736E3F.4040008@...>, dated Fri, 16 Sep 2011, Bhakakhan <bhakakhan@...> writes:

Indeed, we should attack users, who attack users - it seems that this is the only language, those pseudo-masters will understand.

Johannes Herrmann / Yahoo Micbuilders Group

P.S. In our group, such an incident is unthinkable. that'll be worth a strike.

On the other hand, is a 'me too' post to a moderator's post in any way helpful? Isn't it liable to make things worse?
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
When I point to a star, please look at the star, not my finger. The star will
be more interesting.

--- In LTspice@..., Helmut Sennewald wrote:

We shouldn't attack users when we don't know about their
knowledge and capabilities. Please keep that in mind.

Hello Helmut,

I think you have mistakenly interpreted my response as an attack
when it was not. In fact, a reading or comprehension problem was
one of several reasonable possibilities to ask about, given that
the original poster claimed to have read the Help topic on the
switch element, yet was unable to see that it clearly stated the
he must provide a model statement.

This section of the Help topic is very short and includes a clear
link to an example schematic, something that would have answered
his questions. Yet for some reason, he did not run the example.
I truly would like to know the reason why not (and why so many
other people seem to have trouble with Help). This really is a
puzzle to me.

I am gradually coming to the conclusion that written words, even
if short and simple, are not always "seen." It may be because
the reader is not a native speaker of English, it may be because
they are faced with an information overload, or it may be that
the "Twitter" generation can't always effectively process
traditional "dry" textbook-style information (i.e., a reading
comprehension problem), or it may be simple laziness (which, I
suppose a person has the right to be - as long as they don't try
to steal the labor of others).

Anyway, I wonder if Help would be more effective if it included
graphical examples or at least hot links to graphical examples
or hotlinks to launch example schematics. The question remains:

How to make Help continue to function as a compact and efficient
reference while also being able to effectively provide answers
that neophytes can actually see, process and put to use?

Regards -- analogspiceman

In message <j4vu3g+ano2@...>, dated Fri, 16 Sep 2011, analogspiceman <analogspiceman@...> writes:

How to make Help continue to function as a compact and efficient reference while also being able to effectively provide answers that neophytes can actually see, process and put to use?

This is, in my experience, a problem with ALL Helps. I could write a 3-screen post but I won't. It's a good PhD project on communication for someone.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
When I point to a star, please look at the star, not my finger. The star will
be more interesting.

--- In LTspice@..., John Woodgate wrote:

--- In LTspice@..., analogspiceman wrote:

How to make Help continue to function as a compact and efficient
reference while also being able to effectively provide answers
that neophytes can actually see, process and put to use?

This is, in my experience, a problem with ALL Helps. I could write
a 3-screen post but I won't.

Well, people keeping complaining about Help, but so far no one,
including the complainers, has been willing or able to offer any
concrete constructive criticism. It remains a puzzle. -- a.s.

In message <j500ob+lpdp@...>, dated Fri, 16 Sep 2011, analogspiceman <analogspiceman@...> writes:

Well, people keeping complaining about Help, but so far no one, including the complainers, has been willing or able to offer any concrete constructive criticism. It remains a puzzle. -- a.s.

It needs a complete re-write, but the necessary combination of skills is extremely rare - a way to put over intricate concepts in simple language AND a deep understanding of LTspice. I have had some success in the first, but I am nowhere in the second.

To do the first, you have initially to forget all you know about the product, program or application and consider ONLY what questions the user is likely to ask. For each question, you then 'switch on' ONLY that part of your product knowledge needed to answer the question. If you feel compelled to add more, formulate another question to introduce the addition.

Hundreds of questions are likely to be required. The limited lists of up to 20 or so, offered by Microsoft and other Helps, are pitifully inadequate. Answers should include examples wherever possible.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
When I point to a star, please look at the star, not my finger. The star will
be more interesting.

On Sep 16, 2011, at 10:24 AM, analogspiceman wrote:

--- In LTspice@..., John Woodgate wrote:

--- In LTspice@..., analogspiceman wrote:

How to make Help continue to function as a compact and efficient
reference while also being able to effectively provide answers
that neophytes can actually see, process and put to use?

This is, in my experience, a problem with ALL Helps. I could write
a 3-screen post but I won't.

Well, people keeping complaining about Help, but so far no one,
including the complainers, has been willing or able to offer any
concrete constructive criticism. It remains a puzzle. -- a.s.

As far as I can see, "constructive criticism" does no good. The
documentation appears to be the sole perview of Mike and it will be
what he wants it to be.

End of story.

I have offered several positive suggestions about documentation
improvement, including the "go check PSpice documentation, its mostly
the same" and put what needs to be put into single document. That was
shot down by you and others. So, what else is one to do?

I would be delighted to contribute to the Wiki, but its not clear how.
The front page of the Wiki says "create an account to contribute" but
there is no link or information about creating an "account".

Clearly,j genuine input is not wanted.

Jim Wagner
Oregon Research Electronics

[Non-text portions of this message have been removed]

On Sep 16, 2011, at 11:12 AM, John Woodgate wrote:

In message <j500ob+lpdp@...>, dated Fri, 16 Sep 2011,
analogspiceman <analogspiceman@...> writes:

Well, people keeping complaining about Help, but so far no one,
including the complainers, has been willing or able to offer any
concrete constructive criticism. It remains a puzzle. -- a.s.

It needs a complete re-write, but the necessary combination of
skills is
extremely rare - a way to put over intricate concepts in simple
language
AND a deep understanding of LTspice. I have had some success in the
first, but I am nowhere in the second.

To do the first, you have initially to forget all you know about the
product, program or application and consider ONLY what questions the
user is likely to ask. For each question, you then 'switch on' ONLY
that
part of your product knowledge needed to answer the question. If you
feel compelled to add more, formulate another question to introduce
the
addition.

Hundreds of questions are likely to be required. The limited lists
of up
to 20 or so, offered by Microsoft and other Helps, are pitifully
inadequate. Answers should include examples wherever possible.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
When I point to a star, please look at the star, not my finger. The
star will
be more interesting.

As a further example, there is not a single screen snapshot in the
whole documentation. It just says "do this... " or "do that...". For
MANY people, that is simply not sufficient. That is not the way that
many people learn.

Another example: the documentation has few REAL examples. Step-by-
step, picture-by-picture, of how you add a model, or a sub-circuit.
Again, words are fine, words are necessary, but words are not
sufficient.

Jim Wagner
Oregon Research Electronics

[Non-text portions of this message have been removed]

In message <744FF547-789E-48F5-9AE6-A4FF04DCCB25@...>, dated Fri, 16 Sep 2011, Jim Wagner <wagnerj@...> writes:

As far as I can see, "constructive criticism" does no good. The documentation appears to be the sole perview of Mike and it will be what he wants it to be.

Mike obviously has a responsibility to ensure that the Help is completely accurate. But to extend that to saying that no improvement will be entertained is not justified.

End of story.

By no means.

I have offered several positive suggestions about documentation improvement, including the "go check PSpice documentation, its mostly the same" and put what needs to be put into single document. That was shot down by you and others. So, what else is one to do?

Simply don't accept the 'shoot down'. You can write, if you choose, your own 'Jim's Guide to LTspice' and put it on your web site or even in the Files or Files -> Tut folders on the list's web site.

I would be delighted to contribute to the Wiki, but its not clear how. The front page of the Wiki says "create an account to contribute" but there is no link or information about creating an "account".

If so, it needs to be fixed.

Clearly,j genuine input is not wanted.

Now, that is NOT a constructive criticism. I hope this message will de-frustrate you, at least a bit.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
When I point to a star, please look at the star, not my finger. The star will
be more interesting.

In message <075FBDBF-7FC5-4AE8-921F-42D73C76DF0D@...>, dated Fri, 16 Sep 2011, Jim Wagner <wagnerj@...> writes:

As a further example, there is not a single screen snapshot in the whole documentation.

I found several. 'Adding attributes', 'Adding the pins' and 'Attached cursors', for example, all include graphics if not exactly screen-shots. 'Colour palette editor' is another.

It just says "do this... " or "do that...". For MANY people, that is simply not sufficient. That is not the way that many people learn.

Agreed; it's not always the best way to communicate.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
When I point to a star, please look at the star, not my finger. The star will
be more interesting.

--- In LTspice@..., John Woodgate wrote:

A constructive, serious answer! Thank you.

[Y]ou have initially to forget all you know about the product,
program or application and consider ONLY what questions the
user is likely to ask.

This much I already supposed, but the reemphasis is appreciated.

Looking back at the original poster's difficulty in processing
this sentence from Help,

"A model card is required to define the behavior of the switch.",

which to me clearly indicates that the user must create a model
statement in which he assigns values to the switch parameters.
Also implied is that this model statement is usually created in
the form of a SPICE text directive and placed upon the schematic.
A complete novice probably wouldn't know this without an example
or pouring over the manual (which I did when I was brand new to
LTspice, by the way).

Also the sentence refers to a model card, which is most likely a
meaningless term to those who weren't around in the days of punch
card input (I wish Mike would expunge that term from any and all
non-historical documentation). Still, these shortcomings would
be overcome and answered by an example, a link to which Help *did*
provide in this case.

For each question, you then 'switch on' ONLY that part of your
product knowledge needed to answer the question. If you feel
compelled to add more, formulate another question to introduce
the addition.

This is really good advice, as it would tend to overcome the
problems from reading comprehension and information overload that
were mentioned earlier. I wonder if this technique can be done
in a way that is compatible with Help remaining an efficient
reference manual. Anyway, thanks for the idea.

Hundreds of questions are likely to be required. The limited
lists of up to 20 or so, offered by Microsoft and other Helps,
are pitifully inadequate.

True, but a well done wiki could offer unlimited possibilities,
both in links and graphics.

Answers should include examples wherever possible.

Well, in the switch example, Help offered,

"See the schematic file .&#92;examples&#92;Educational&#92;Vswitch.asc to see
an example of a model card placed directly on a schematic as a
SPICE directive.",

which the original poster seemed not to have read (or at least
ignored, hence my legitimate question about the possibility of
there being either a reading comprehension problem or laziness at
play). Note that this example would have answered any lingering
questions about what "a model card" could mean.

Regards -- analogspiceman

In message <j50avg+6kln@...>, dated Fri, 16 Sep 2011, analogspiceman <analogspiceman@...> writes:

Well, in the switch example, Help offered,

"See the schematic file .&#92;examples&#92;Educational&#92;Vswitch.asc to see an example of a model card placed directly on a schematic as a SPICE directive.",

I would add a few more words. 'Open the downloaded LTspiceIV folder, open examples and then Educational, and open the schematic file Vswitch.asc'....

In doing that, I've assumed no more than beginner level understanding of Windows (at least in English) as well. That dot in

.&#92;examples&#92;Educational&#92;Vswitch.asc

hides a lot of meaning.

which the original poster seemed not to have read (or at least ignored, hence my legitimate question about the possibility of there being either a reading comprehension problem or laziness at play). Note that this example would have answered any lingering questions about what "a model card" could mean.

It would certainly have minimised doubt anyway, but I agree with you that 'card' [and 'deck'] are archaisms that should be eliminated.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
When I point to a star, please look at the star, not my finger. The star will
be more interesting.

Another problem with the LTspice Help, is that just about everything
starts with the old non-graphical input format of traditional (i.e.
Berkeley) SPICE:

Syntax: Sxxx n1 n2 nc+ nc- <model> [on,off]

Example:

S1 out 0 in 0 MySwitch

.model MySwitch SW(Ron=.1 Roff=1Meg Vt=0 Vh=-.5 Lser=10n Vser=.6)

And then we tell everyone to use the schematic editor, and upload
schematic files instead of netlists.

So the Help file is a little like using DOS in a Windows world.

Plus the references to a SPICE "deck", a model "card", etc. Imagine
if the Help for MS-Windows gave everything in terms of DOS commands
and command-line switches.

It probably makes little sense to anyone coming to LTspice for the first time.

For those of us who used SPICE before, the relationship between the
element and the model, by way of the model name, was obvious. And we
take for granted that the element is now a schematic symbol, but the
model is a "SPICE directive" ... which is mentioned in the Help
description but not really explained.

So yes, there are lots of problems.

Andy

Hello Jim,

I agree it should be easier to find help when one needs it. In your case how to create an account on LTwiki. But then once the account is created, the instructions how to do so become irrelevant and thus clutter.

So a bit of poking around reveals that signup info is in LTwiki - toolbox - special pages - Login / signup.

As one wise old sage remarked - ...there must be a pony here somewhere! It is just up to us to find it. As frustrating as it is, I have resigned myself to this a long time ago.

Respectfuly

ME

LTwiki.org <> is now fixed on the front page with a
link on how to create an 'account'. This capability also exists if one
tries to 'log in'. Sorry, I did not try to make it hard, only the
anonymous spammers were taking many hours of my day to roll back their
destructive work.
Create an LTwiki account
<> Thanks
everyone for a great online community. Lewis


--- In LTspice@..., John Woodgate <jmw@...> wrote:

I would be delighted to contribute to the Wiki, but its not clear

how.

The front page of the Wiki says "create an account to contribute" but
there is no link or information about creating an "account".

If so, it needs to be fixed.

Clearly,j genuine input is not wanted.