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--- In LTspice@..., "jerrylee.marcel" <jerryleemarcel@...> wrote:

Hi,
I've posted a .asc in Files-> Temp names Step gain control.
I expected it to display a family of 21 graphs but it just
shows the default graph corresponding to the default value
of the potentiometer.
What did I do wrong?

Hello,

Please also upload your symbol potentiometer1.asy and your model
potentiometer.sub.

Best regards,
Helmut

In message <ktmej9+q42f@...>, dated Sun, 4 Aug 2013, jerrylee. marcel <jerryleemarcel@...> writes:

I've posted a .asc in Files-> Temp names Step gain control. I expected it to display a family of 21 graphs but it just shows the default graph corresponding to the default value of the potentiometer. What did I do wrong?

You need to set wiper={p2}, not the fixed value of 0.5, and change w in ".step param w 0 1 0.1" to p2 (no curly brackets).

Why do you expect 21 graphs, with only eleven steps? Is it a stereo pot? (;-)
--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Hi,
I've posted a .asc in Files-> Temp names Step gain control.
I expected it to display a family of 21 graphs but it just shows the default graph corresponding to the default value of the potentiometer.
What did I do wrong?

Hello Olek,

I remember that I tried and the simulation took too long for
my free time. Please be aware that practically no user of this
group is an employee of LTC.
Why not asking your nearly located FAE (Filed Application Engineer)
from LTC? They may be able to help.

Best regards,
Helmut

PS: I am also not an employee of LTC.

Really nobody is able to help me ?
I need a solution to get an isolated dc/dc converter with Vin = +8...30V and Vout = +3.2...4.3V at Iout=20 A.
The LTC3765 & 66 chips seems to be a nice solution, but at lower Vin this combo doesn't simulate peoperly/


Thanks in advance, OlekA

Hi. Actually LTspice can open a .sch file (try it!), and it deciphers the
symbols into it's own "translated symbols" directory. It tries to
translate the associated netlists, buy seems to only be able to deal with
the rudimentary elements (resistors etc.)

Wow, I would not have thought it possible, given that their origins are so
different. It's good to learn something new every day.

the other Andy

Dear all,
to solve problems like this a "symbolic link" could be used.
This allows to have your own library in any directory.
A nice tool to create a symbolic link in a comfortable way would be "link shell extension"

Erich

Hi. Actually LTspice can open a .sch file (try it!), and it deciphers the symbols into it's own "translated symbols" directory. It tries to translate the associated netlists, buy seems to only be able to deal with the rudimentary elements (resistors etc.)
-Andy

Hi All,

Using the examples Helmut directed me to, I put together a circuit, DiodeNoiseCircuit.asc, available in the temp directory. I'm very confused about the need for the capacitor in parallel with the diode. At frequencies where all the current effectively goes through the capacitor and the diode current is effectively zero, the shot noise is correct: sqrt(2*I1*1.602e-19). When the current is all flowing through the diode, which is when I would expect the shot noise to be as calculated, there is no shot noise. Can anyone enlighten me as to why this is the case?

Thanks in advance,
Darren

Do you mean that LTspice will understand the netlist from Pspice, or that
it will understand my whole model, including schematic?

Netlists. LTspice is "very" compatible with PSPICE netlists. There are a
few things that do not work directly, but most things do.

The schematic file formats are proprietary to each program. There is no
chance of reading a PSPICE schematic directly into LTspice. I don't know
if there is a conversion program (I have not heard of one).

Andy

Hi Helmut,
Do you mean that LTspice will understand the netlist from Pspice, or that it will understand my whole model, including schematic? I know that it will understand the netlist, but I'm trying to migrate my schematics, which include analog-behavioral parts (like E and G). I've tried to simply open the Pspice schematics (.sch) in LTspice, but the translation usually doesn't work somehow...

Thanks,
Andy

Andy Helmut can delete this stuff any time he likes, everything is in
the TEMP files except for one photo I just put in the photos "triplexer" album.

Decided I am going to move this project to QUCS and see if they can help me with the s-parameter stuff.

WW

I might suggest putting the articles about triplexers somewhere other than
the [LTspice] group, unless they are directly related to LTspice. The
group's file space is limited.

Andy

...sorry guys I meant QUCs not Oregano.

Going to upload what I have, was trying to compress the RF Design

cover photo, but its over 65 MB. The output graphics also I am having

difficulty posting, every time I send the email back to myself, I get

a blank dark panel...no "colored lines". I am just glad I don't

really need this circuit, it is just an experiment. I also have

several articles on microwave and uhf "triplexers",and will enclose

those documents with the files.

Uploading for the group then, look for the "Triplexer" file.

W. Warren

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

I am in the process of updating the depth and accuracy of the
historical SPICE page over at the LTwiki:

But what I am looking for right now is to complete the section
about PSpice. Specifically, I have no idea who were the people
initial responsible for creating PSpice. [...] Also, I could
not find any information as to when and at what revision Probe
became a part of PSpice. (Perhaps at the initial release?)

Then there is the meaning of name itself. I vaguely recall that
PSpice was at some point called uPspice (the 'u' being a micro
symbol), thus the acronym may have stood for micro-Processor SPICE
(others suggest it meant "Personal SPICE" or "Personal-computer
SPICE").

Okay, after a lead from Tony Casey and some further research, I
found Paul Tuinenga's current website (he was a founder of PSpice),
contacted him and got a very nice response (but he forgot to answer
all the questions!). Here is part of his response that he offer to
be shared:

"PSpice was launched in Jan 1984, with a short paragraph in
Electronics (McGraw Hill) magazine. I have a photocopy of that
announcement, but it's 700 miles away from me just now.

"'P' stands for Personal, as in Personal Computer (PC). MicroSim
(an invented name... having first checked the advertising list in
Byte magazine) stands for SIMulation on MICROprocessors. As it
turns out, the main product idea of the company was a mistake.
Between the summer of 1984 and the spring of 1985, we built an
accelerator based on multiple Intel 8086s (with 8087 floating-point
coprocessors), two complete computers per Multibus board, and systems
with up to 12 boards. The external box attached to an IBM-PC/AT and
provided over 2x the speed of a DEC VAX-11/780 minicomputer (which
many companies were using 24x7 to run UCB SPICE). It was called
PSpice Turbine. We sold one a week after debuting it at an EDN
industrial conference. Then the industry went into a capital-
spending slump and we didn't sell another for the rest of that year.
In the meantime, PSpice the "shrink wrap" software, the sales of
which were to "keep us in baloney sandwiches" until the real product,
the Turbine hardware accelerator, took off. It never did, but every
month the sales of PSpice grew. So we shelved the hardware
development to re-focus on the software e.g. re-writing it from
Fortran into C (then C++ much later)."
_______________________________________________________________

After thanking him for his gracious response, I posed a few more
questions: "When did you first begin working on what was to become
MicroSim/PSpice (and when was MicroSim first officially launched -
1983)? Also, were you the sole (major) founder or did you have
other equal partners?" (Forgot to ask again when Probe became
part of PSpice.)

Anyway, I've updated the LTwiki to include the new information.

!!!Hold on, on just now received an email from Paul Tuinenga.
Here is some of the part okay to be shared:

"The creator of PSpice is Wolfram Blume (BS75 Caltech). He sat in
the office next to mine at Silicon Systems, Inc. (SSi), In 1983,
SSi bought several IBM-PC/XTs. Blume was the in-house maintainer
of UCB SPICE on the Prime minicomputers used for IC design and
layout at that time. SSi developed most of the tools it needed
(and we all take for granted today) because none existed at the
time. For example, SSi was the first to make color plots of IC
layouts, and using stipple patterns for the layers (these overlap
in a visually pleasing way). We also created a layout-versus-
schematic (LVS) that predates by several years anything from the
ECAD vendors.

"Knowing the innards of SPICE, and where the time was spent for
transient simulations, Blume got the idea to see how fast the
IBM-PC was. He tested the speed of MOS level -2 code using the
Microsoft Fortran compiler. As is turns out, that test gave an
optimistic result for Intel processors to accelerate simulations
and thus propelled the idea of MicroSim.

"The problem with SPICE being shoehorned into the PC (640KB max
memory) is SPICE2 was five(?) overlays and no IBM-PC Fortran
compiler had overlay capability. Blume figured out how to replace
those as two programs run in sequence, with the first doing read-
in and checking, then leaving a data structure in memory for the
analyses to operate on in the second program. This is why MicroSim
PSpice had no competition for about two years, until later IBM-PC
Fortran compilers handled overlaying.

"SSi was officially upset with Wolfram and "Blume Engineering"
selling PSpice for $495, and demanded royalties. Blume quit SSi.
Shortly after, he and I met to discuss his situation. He described
this idea for building a hardware accelerator. He's not a hardware
guy, but I am and I knew exactly how to build it. So I quit SSi,
too, and we formed MicroSim in June 1984. Blume was the major
partner."

"Later, when the Turbine fizzled, I turned to software and rewrote
all the device equations into C. Then I created the Parts option
and built up the several thousand standard components library.
Also, I wrote "the book" which eventually went to three editions
(additional material in each), was translated to Japanese and
French, and sold well over 100,000 copies. That last sounds small,
but for technical books, which normally sell in the mid 4-figure
volume range, I am Steven King. OK, I wrote a pretty good book,
but Prentice Hall gets all the credit for pushing it far and wide.
Dr. Richard Newton told me he saw a copy in a Moscow university
office (long before the Soviet empire fell)."
_______________________________________________________________

Below are first the LTwiki SPICE history page introduction, then
the section just about MicroSim PSpice (now needing revision:
_______________________________________________________________

LTspice excels, not only in its technical prowess, but also in its
unique accessibility to and popularity with the masses. This page
highlights the heritage of LTspice, emphasizing both the technical
developments leading up to the current version of LTspice and the
key events and prior trailblazers on the pathway to making SPICE
the dominant simulation platform in the engineering community.

If as its primary original author, Larry Nagel is deservedly
considered "The Father of SPICE" then as its essential enabler,
advocate and general all-round visionary for open source electronic
simulation software, Don Pederson most certainly is SPICE's god-
father. And its two most noteworthy disciples and popularizers
would have to be Paul Tuinenga and Mike Engelhardt. These are men
who clearly could see the power and potential of SPICE, had the
ability to hone it into practical tools and, most importantly had
the genius to make SPICE a comfortable fixture on the majority of
engineering desktops.
_______________________________________________________________

1984: PSpice (Personal-Computer SPICE)

Caltech graduate, Paul Tuinenga (MS78), co-founds MicroSim as V.P. of Technology circa 1983

Developed to run on the first IBM PC, PSpice is initially released in January 1984

Was the first commercial offspring of Berkeley SPICE to run directly on the PC platform

Last FORTRAN version was 2.06 – version 3.00 (Dec 86) was rewritten totally in C, yielding a 20% speed increase

Feedback from a very large customer base led to rapid convergence, speed and feature enhancements

Was the first SPICE program to gain wide acceptance in both industry and academia
- Paul Tuinega's tutorial, SPICE: A Guide to Circuit Simulation and Analysis Using PSpice, (now in its 3rd edition) becomes the "New Testament" of SPICE

KEY EVENT: A zero cost (but node-limited) student version was introduced in 1988
- For the first time, SPICE became truly ubiquitous in the electrical engineering academic and industrial communities

Evolved from Berkeley SPICE 2G, but added many proprietary enhancements
- Dec 86: nonlinear Jiles/Atherton core model, Apr 87: ideal switches, Date?: proprietary IGBT model (and many other enhancements)
- Probe, a waveform viewer module, was added when PC VGA graphics became available
- Schematics, a graphical front end, was added much later with version 5.00 in July 1991

In January 1998 MicroSim was acquired by OrCAD, which itself was subsequently purchased by Cadence Design Systems in July 1999

--- In LTspice@..., "William" <wms121@...> wrote:

..I have a "working circuit', but it's not exactly performing as

desired. The problem is I am not sure exactly what the expected

performance is. I could send it to you rather than post it in the

files section. It is a possible "bogus schematic" from the cover

of the January 1985 issue of RF Design..(now defunct) and I am not

sure "it was ever designed to work".

I got it biased up so to speak, but LTSPICEIV is not exactly setup for

s-parameters and I think you would need that capability to test it

properly. I want to take this circuit into Oregano with its microwave

and scattering parameters capabilities to check it completely.

Sending an attached set of documents to your email address.


W. Warren

Hello William,

I really prefer that people upload their circuits to Files>Temp.

S-parameters are only for linearized circuits. This means there
is no DC operating point information in the S-parameter file.
The whole circuit around should not feed DC voltage into the
S-parameter component.

Best regards,
Helmut

--- In LTspice@..., "William" <wms121@...> wrote:

..I have a "working circuit', but it's not exactly performing as

desired. The problem is I am not sure exactly what the expected

performance is. I could send it to you rather than post it in the

files section. It is a possible "bogus schematic" from the cover

of the January 1985 issue of RF Design..(now defunct) and I am not

sure "it was ever designed to work".

I got it biased up so to speak, but LTSPICEIV is not exactly setup for

s-parameters and I think you would need that capability to test it

properly. I want to take this circuit into Oregano with its microwave

and scattering parameters capabilities to check it completely.

Sending an attached set of documents to your email address.


W. Warren

I'm sure Helmut won't mind my answering on his behalf. If you upload your schematic (and all required models and symbols) to Files>Temp (as described on the group homepage), instead of burdening Helmut with "bogus schematics", you might get the attention of up to 30000 other members of this group.

Indeed, LTspice is not ideal for RF design, but it can be used quite effectively with a little effort. As far as Oregano is concerned, this is not a simulator for RF and Microwave. It simply is front-end for ngspice or GNUcap, neither of which handle S parameter any better than LTspice. I would point out that you don't have to have a circuit "biassed up" to analyse its performance if you have its S parameters.

Two free simulators that do handle S natively parameters are: RFsim99 and QUCS.

If you have a picture of the circuit you're trying simulate, I'm sure someone here can quickly tell you what it's supposed to do, if you're not sure, as you say.

Regards,
Tony

..I have a "working circuit', but it's not exactly performing as

desired. The problem is I am not sure exactly what the expected

performance is. I could send it to you rather than post it in the

files section. It is a possible "bogus schematic" from the cover

of the January 1985 issue of RF Design..(now defunct) and I am not

sure "it was ever designed to work".

I got it biased up so to speak, but LTSPICEIV is not exactly setup for

s-parameters and I think you would need that capability to test it

properly. I want to take this circuit into Oregano with its microwave

and scattering parameters capabilities to check it completely.

Sending an attached set of documents to your email address.


W. Warren

It would be a good idea to list it on the groups webpage but alas the people that don't read the help files (many) will also not look at the blog, kind of sad, but that is people for you.

Thanks for the link.

Cecil - k5nwa

In message <ktih8q+c1i9@...>, dated Sat, 3 Aug 2013, Tony Casey <tony@...> writes:

I would venture to suggest that many people are unaware, as I was, that Linear Technology now has an official LTspice IV blog.

It seems that only LT people can post, which means it's no threat to this mailing list, as it would be if anyone could post.
--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK