Re: In need of some zeners or maybe model them myself
On Mon, Feb 3, 2025 at 04:46 PM, John Woodgate wrote:
The first step is to search the groups archives from the web site Files page. Then ask the manufacturer, found by a web search - STI in the case of the 1N4572, Microchip for 1N5226, etc.
I tried the group archives a couple of different ways but was unsuccessful. As far as STI, what is that an acronym for again? As far as Microchip, their site has not been helpful so far. Got the data sheet but, can't find a spice file. Tried it again just now and, still no spice file. As with most data sheets, I believe I have most of what I need to model my own if I have to. Thoughts? In the meantime, let me know about STI.
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Re: In need of some zeners or maybe model them myself
On Mon, Feb 3, 2025 at 04:41 PM, Andy I wrote:
Ivan,
?
When looking for models, consider these:
- Search the Internet (part vendor sites) for "equivalent" parts.
- Go to the group's Files section, and type in the model number in the Search box in the upper right corner.
I searched the vendor sites but have so far come up empty. I will try again. I did also search on this site but, nothing came up for any of these parts. Finally, I tried perusing that long ass set of links from the old yahoo group but, there's just way too many links to go through. I got maybe a quarter way through before I gave up.
- Consider omitting the suffix (A or B) if you understand what it does.? Often it does not matter.
I can check the data sheets to see if there are any differences but, even if it does, and I do find a model file like the one you posted below, can't I just change the one or two parameters that may be different in the datasheets and then, after updating the model file, save the model file under a new model name?
- Find a similar zener from among LTspice's built-in diodes.? I recommend this way:
- Start with a Zener symbol, right-click on the symbol, then click "Pick New Diode".
- Now click "Vbrkdn[V]" at the top, THEN click "Type" at the top.? Now they will be sorted into diode types, followed by breakdown voltage.
- Scroll down until you find the Zeners.? Then look for the same or a similar voltage.
- Try to find a diode with similar power ratings.
- ?
I will try that
- Find a similar zener by checking manufacturer's part selector guides; they often list "equivalent" or "replacement" parts.
Tried that but, I will try again.
- For a zener, if you plan to use it only in breakdown, many of the SPICE characteristics won't matter, and you can probably get away with a very crude or approximate model.
That's what I'm figuring.
I found a 1N5226 (no B) model in our Files. It says its source was Motorola:
* 1N5226 ? ?3.3 Volt ?5% ?W zener diode
.model D1N5226 ?D(Is=31.47f Rs=9.494 Ikf=0 N=1 Xti=3 Eg=1.11 Cjo=220p M=.5959
+ ? ? ? ? ? ? ? Vj=.75 Fc=.5 Isr=2.035n Nr=2 Bv=3.3 Ibv=45.862m Nbv=3.0477
+ ? ? ? ? ? ? ? Ibvl=29.831m Nbvl=11.606 Tbv1=-636.36u)
* ? ? ? ? ? ? ? Motorola ? ? ? ?pid=1N5226 ? ? ?case=DO-35
* ? ? ? ? ? ? ? 89-9-18 gjg
* ? ? ? ? ? ? ? Vz = 3.3 @ 20mA, Zz = 310 @ 1mA, Zz = 68 @ 5mA, Zz = 19 @ 20mA
?
This looks like a PSpice file, no? From what I understand, LTSpice can read them no problem, right? Or, do I have to remove that first D in the name, for example, in order for LTSpice to recognize it? I'm assuming I just copy and paste this into a text file and name it 1N5226.lib or .mod or something and try it out, no? If it works, I can just add it to my user.dio file.
I thought I found a 1N4572 model in our Files, but alas it was not.? I did not find the 1N5241 model but LTspice comes with one for 11.0 V and others nearby.??I did not find 2N3791 in our Files.
?
Yeah. It's been a bitch to find these files. Either way, thanks again for all your help.
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Re: In need of some zeners or maybe model them myself
On Mon, Feb 3, 2025 at 04:57 PM, Tony Casey wrote:
Wow! Have you seen the price of 2N3791s? They haven't been made for decades. Why are you using them?
--
Regards,
Tony
?
I'm actually trying to simulate a device we make at work. I work at a small company and their stuff is old as hell. Lol! The company has been around for 40 or so years so, a lot of the devices were designed with really old components and..., they've never been updated. In my department specifically, we still used DOS programs up until our testing rig died about two years ago. Lol! Every so often something goes obsolete and the department head has to scramble to find a replacement. Unfortunately, most of our stuff has to meet government standards so, changing one component to another is a real PITA and, time consuming. Worse still, they fired their last engineer here about two years ago so, no one actually knows how any of our products really work at the deepest component level. Don't know how the company is staying afloat. In any case, I am trying to up my game some to eventually ask for more money. :) We're mostly in production mode all the time but, quite often we also have to troubleshoot and fix stuff. Most are easy fixes but, this one device has been a mystery to us all. Not completely but, enough where we just don't know what to make of certain anomalies when they pop up. Either way, if I could simulate this device, I think it'll really help me understand some things better.
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On Mon, Feb 3, 2025 at 03:57 PM, <rlim701@...> wrote:
Just uploaded LG_single.asc.
That's good -- but it does not fully help.? Your main schematic (heng-24v.asc) wants to load the symbol named "LG_single".? That symbol is a file named "LG_single.asy", which is still on your computer only.? None of the rest of the world can try your simulation because none of the rest of us has that symbol file.
?
Maybe you don't want us to try your simulation, and that is sort of OK if it's true.? But wouldn't it help to give us all the parts so that we can try it?? Sometimes, someone else may discover something that a single pair of eyes doesn't find.
?
As it appears, that symbol file represents the lower-level hierarchical block in the schematic "LG_single.asc".? So we now have THAT file.? But we are still missing the symbol that represents that lower schematic on your main schematic.? Without it, there's a hole in your schematic and some missing current paths, causing the distortion to exceed 1%.
?
Andy
?
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Re: In need of some zeners or maybe model them myself
Old Hi-Fi?
On 2025-02-03 21:56, Tony Casey wrote:
Wow! Have you seen the price of 2N3791s? They haven't been made
for decades. Why are you using them?
--
Regards,
Tony
On 03/02/2025 22:01, Ivan via
groups.io wrote:
Been looking for some components here, there and
everywhere, and I am having a hard time finding them. I'm
looking for 3 zeners and a power transistor.
?
Zeners:
1N4572A 6.4V Zener
1N5226B 3.3V Zener
1N5241 11V Zener
?
Transistor:
2N3791
?
Any help would be appreciated. I am totally down with
trying to model it myself via their datasheets, and have some
idea of how to do that but, I've never attempted that before
so, any push in that direction would help too. It might help
if I could find equivalents that may be in the LTSpice library
that I could use or, equivalent enough that I can change some
of the it's values in order to create what I need. Of course,
I'm checking YT for help in these department but, if there's a
model out there, it would be a lot easier. I did find one text
doc that is supposed to be a library of models that includes
the 1N5226B but, it's very difficult to see what is what in
that file. I started re-writing / re-organizing it into
something that looks like a library of models but, don't know
if it'll amount to anything. I was planning on uploading it
here and see what you guys make of it. Let me know.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Is there a good reason why you are performing the the .FOUR over 61
cycles? You don't get a more accurate answer using more cycles.
Unless you have some time-varying perturbation going on, why not use
.FOUR with its default setting, which is 1 cycle? Try that and see
if it fixes your issue.
--
Regards,
Tony
On 03/02/2025 21:14, rlim701 via
groups.io wrote:
toggle quoted message
Show quoted text
Alright, guys.? I
uploaded heng-24v.asc and heng-models.txt.? I have a
'throw_cycles' parameter that throws away cycles before doing
.four.? If I set that to 100, I see THD=0.002% but when I set that
to >1000, reported THD is always 0.000000%.? Setting numdgt to
16 did not make a difference.
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Sorry, I missed that it is supposed to be used with another
schematic.
For future reference, it is best to upload all required files
packaged in a zip, not separately. that makes it easier and more
convenient for sharing.
--
Regards,
Tony
On 03/02/2025 23:07, Tony Casey wrote:
toggle quoted message
Show quoted text
Are
you sure you uploaded the right schematic? LG_single.asc doesn't
even have an analysis directive. It just looks like a loop probe,
which designed to be used in .AC analyses, anyway.
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Are you sure you uploaded the right schematic? LG_single.asc doesn't
even have an analysis directive. It just looks like a loop probe,
which designed to be used in .AC analyses, anyway.
--
Regards,
Tony
On 03/02/2025 21:57, rlim701 via
groups.io wrote:
toggle quoted message
Show quoted text
Just uploaded
LG_single.asc.? It did not make any difference whether I am using
version 24.0.12 or 24.1.1.? Andy, I think I see where you are
going.? Still trying to digest your post.....
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Re: In need of some zeners or maybe model them myself
Ivan, when you said you had already looked here, there, and everywhere, I assume you searched the Internet for these parts, and found their webpages from the manufacturers that make them.
?
Most (not all) manufacturers have SPICE models for simple parts like diodes and zeners.? But it can sometimes be challenging to find them from their websites.? If you found their website but there is no sign of a SPICE model, I advise you to look more closely.? Sometimes it is a challenge to find them.
?
Andy
?
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Re: In need of some zeners or maybe model them myself
Wow! Have you seen the price of 2N3791s? They haven't been made for
decades. Why are you using them?
--
Regards,
Tony
On 03/02/2025 22:01, Ivan via groups.io
wrote:
toggle quoted message
Show quoted text
Been looking for some components here, there and everywhere,
and I am having a hard time finding them. I'm looking for 3
zeners and a power transistor.
?
Zeners:
1N4572A 6.4V Zener
1N5226B 3.3V Zener
1N5241 11V Zener
?
Transistor:
2N3791
?
Any help would be appreciated. I am totally down with trying
to model it myself via their datasheets, and have some idea of
how to do that but, I've never attempted that before so, any
push in that direction would help too. It might help if I could
find equivalents that may be in the LTSpice library that I could
use or, equivalent enough that I can change some of the it's
values in order to create what I need. Of course, I'm checking
YT for help in these department but, if there's a model out
there, it would be a lot easier. I did find one text doc that is
supposed to be a library of models that includes the 1N5226B
but, it's very difficult to see what is what in that file. I
started re-writing / re-organizing it into something that looks
like a library of models but, don't know if it'll amount to
anything. I was planning on uploading it here and see what you
guys make of it. Let me know.
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Re: In need of some zeners or maybe model them myself
On Mon, Feb 3, 2025 at 04:01 PM, Ivan wrote:
I did find one text doc that is supposed to be a library of models that includes the 1N5226B but, it's very difficult to see what is what in that file.
Beware.? There is at least one long list of library parts, which I've seen uploaded in this group a few times, but they are not the models.? It is just a list of the parts that you could get, if you installed a separate program or purchased someone's library.? I don't know if this is what you saw, but it might be.
?
On the other hand, it could be a library of models.? If it seems difficult to read, it might be a text file formatting thing.? Some text files use CR/LF characters between lines, some use just CR or just LF, and some use LF/CR.? Windows's Notepad can't display all of them correctly.? Try another text editing program.
?
Another possibility is that it is an encrypted file, but that is less likely.
?
Andy
?
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Re: Models LM317 and LM337 made by the same hand
I just uploaded the file, Dual PSU simplified.zip
A first level simplification of the Dual Power Supply, for Andrea Patuelli.
Just one LM337 for the negative channel, as a working point.
?
I couldn¡¯t read the part number of the? three terminal reference diode, so replaced it with a single Silicon diode to create a slight positive reference to permit the variable pot to cover a reasonable range.
Also, had to assume the output was to be 3.3V, based upon the Zener on the output.
?
Look at this as a start, add the positive side, then the extra ¡°paralleled¡± regulators, to flesh it out.
?
Dave Bell
?
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Re: In need of some zeners or maybe model them myself
The first step is to search the groups
archives from the web site Files page. Then ask the
manufacturer, found by a web search - STI in the case of the
1N4572, Microchip for 1N5226, etc.
On 2025-02-03 21:01, Ivan via groups.io
wrote:
Been looking for some components here, there and everywhere,
and I am having a hard time finding them. I'm looking for 3
zeners and a power transistor.
?
Zeners:
1N4572A 6.4V Zener
1N5226B 3.3V Zener
1N5241 11V Zener
?
Transistor:
2N3791
?
Any help would be appreciated. I am totally down with trying
to model it myself via their datasheets, and have some idea of
how to do that but, I've never attempted that before so, any
push in that direction would help too. It might help if I could
find equivalents that may be in the LTSpice library that I could
use or, equivalent enough that I can change some of the it's
values in order to create what I need. Of course, I'm checking
YT for help in these department but, if there's a model out
there, it would be a lot easier. I did find one text doc that is
supposed to be a library of models that includes the 1N5226B
but, it's very difficult to see what is what in that file. I
started re-writing / re-organizing it into something that looks
like a library of models but, don't know if it'll amount to
anything. I was planning on uploading it here and see what you
guys make of it. Let me know.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
Re: In need of some zeners or maybe model them myself
Ivan,
?
When looking for models, consider these:
- Search the Internet (part vendor sites) for "equivalent" parts.
- Go to the group's Files section, and type in the model number in the Search box in the upper right corner.
- Consider omitting the suffix (A or B) if you understand what it does.? Often it does not matter.
- Find a similar zener from among LTspice's built-in diodes.? I recommend this way:
- Start with a Zener symbol, right-click on the symbol, then click "Pick New Diode".
- Now click "Vbrkdn[V]" at the top, THEN click "Type" at the top.? Now they will be sorted into diode types, followed by breakdown voltage.
- Scroll down until you find the Zeners.? Then look for the same or a similar voltage.
- Try to find a diode with similar power ratings.
- Find a similar zener by checking manufacturer's part selector guides; they often list "equivalent" or "replacement" parts.
- For a zener, if you plan to use it only in breakdown, many of the SPICE characteristics won't matter, and you can probably get away with a very crude or approximate model.
?
I found a 1N5226 (no B) model in our Files.? It says its source was Motorola:
* 1N5226 ? ?3.3 Volt ?5% ?W zener diode
.model D1N5226 ?D(Is=31.47f Rs=9.494 Ikf=0 N=1 Xti=3 Eg=1.11 Cjo=220p M=.5959
+ ? ? ? ? ? ? ? Vj=.75 Fc=.5 Isr=2.035n Nr=2 Bv=3.3 Ibv=45.862m Nbv=3.0477
+ ? ? ? ? ? ? ? Ibvl=29.831m Nbvl=11.606 Tbv1=-636.36u)
* ? ? ? ? ? ? ? Motorola ? ? ? ?pid=1N5226 ? ? ?case=DO-35
* ? ? ? ? ? ? ? 89-9-18 gjg
* ? ? ? ? ? ? ? Vz = 3.3 @ 20mA, Zz = 310 @ 1mA, Zz = 68 @ 5mA, Zz = 19 @ 20mA
?
I thought I found a 1N4572 model in our Files, but alas it was not.? I did not find the 1N5241 model but LTspice comes with one for 11.0 V and others nearby.??I did not find 2N3791 in our Files.
?
Andy
?
?
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Re: Models LM317 and LM337 made by the same hand
That's not easy, as the LM317 model is a transistor level model. I don't know how close it is to reality. In this respect, behavioural models are easier to work with.
This is a good illustration of where a device level model isn't necessarily better than a behavioural one.
Unfortunately, I don't have the time right now to look into this further. Perhaps someone else can step up.
-- Regards, Tony
On 3 Feb 2025 20:07, "andrea.patuelli via groups.io" <andrea.patuelli@...> wrote: All OK Tony. I learned how to include your .mod files. Now for setting on LM317 the Vref from 1,319 to 1,25, How I can do?
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In need of some zeners or maybe model them myself
Been looking for some components here, there and everywhere, and I am having a hard time finding them. I'm looking for 3 zeners and a power transistor.
?
Zeners:
1N4572A 6.4V Zener
1N5226B 3.3V Zener
1N5241 11V Zener
?
Transistor:
2N3791
?
Any help would be appreciated. I am totally down with trying to model it myself via their datasheets, and have some idea of how to do that but, I've never attempted that before so, any push in that direction would help too. It might help if I could find equivalents that may be in the LTSpice library that I could use or, equivalent enough that I can change some of the it's values in order to create what I need. Of course, I'm checking YT for help in these department but, if there's a model out there, it would be a lot easier. I did find one text doc that is supposed to be a library of models that includes the 1N5226B but, it's very difficult to see what is what in that file. I started re-writing / re-organizing it into something that looks like a library of models but, don't know if it'll amount to anything. I was planning on uploading it here and see what you guys make of it. Let me know.
|
Just uploaded LG_single.asc.? It did not make any difference whether I am using version 24.0.12 or 24.1.1.? Andy, I think I see where you are going.? Still trying to digest your post.....
|
Richard,
?
I don't know if this makes any difference (since I can't try your simulation).? I am only suggesting it as something to try.? Your simulation saves data for 61 cycles, then it asks the .FOUR to calculate harmonics over exactly 61 cycles.? But what if round-off causes the simulated interval to be ever slightly smaller than 61 cycles?? Can you save data for 61 cycles, then set the .FOUR's Ncycles to 60?
?
Andy
?
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Richard,
?
You forgot to upload the symbol file LG_single.asy.? We can't see your whole schematic, nor run the simulation, without it.? If you forgot the symbol, you might have forgotten its model too.
?
It makes perfect sense that throwing away more cycles (waiting for things to stabilize) results in lower distortion.
?
It also makes sense that there is a point at which you just can't make the calculations any better.
?
Which version of LTspice are you using?? There are known bugs with NUMDGT in the latest version, 24.1.1 - which is turning out to be a major disaster, by the way.
?
Andy
?
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Alright, guys.? I uploaded heng-24v.asc and heng-models.txt.? I have a 'throw_cycles' parameter that throws away cycles before doing .four.? If I set that to 100, I see THD=0.002% but when I set that to >1000, reported THD is always 0.000000%.? Setting numdgt to 16 did not make a difference.
Thanks in advance,
Richard
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John Woodgate
Tony Casey
Bell, Dave