Ltspice is a big dissapointment !

[eTobey]

Hi,

i wonder why everyone is using (it seems) ltspice. Its like working with a software from 199X, and i dont talk about the looks of it. Hotkeys that other programs have, ltspice does not use like undo for example.

Simulating a button with a relais(?) and a voltage source? It also looks pretty ugly, as the switch does have its "+" on the bottom...
And on top of that, it doesnt even work (cant find the model).

Also a cant probe a node that i have named "base"

Seriously???

With those limitations i tend to stick with falstad and then test my own circuits.

What about QUCS?? Is it better with this?

[JohanH]

Keep in mind SPICE was developed in 1970's. There are not many different good free simulators out there and Ltspice isn't even open source (even though popular). Qucs and ngspice are better in this regard. It's still almost necessary to know the spice syntax. I haven't really worked with the GUI tools, but doesn't feel like they are much better than 20 years ago.

[RoGeorge]

Disappointment is nothing but wrong expectations. 
LTspice is a great tool once you'll get accustomed to it.

If you think LTspice GUI is bad, just try QUCS.
That will make LTspice seem gorgeous. 

[iMo]

F9 is undo. There are dozens of various switches, you have to download and install libraries.
https://groups.io/g/LTspice
LTSpice is not an interactive toy, you have to program the behavior of the switches.
When you name a wire "base" you can easily probe it..
I never had a problem with copy/paste something off the results windows in LTSpice..
Get a little bit familiar with the LTSpice, it is a great tool..

[RoGeorge]

Also, the keys can be reassigned from the LTspice menu Tools -> Control Panel -> Drafting Options -> Hot Keys

Click on each tab and each key you want to change, even if that may seem grayed out.
I use CTRL+Z for undo, and redefined almost all the other shortcut keys and colors, too.

[vk6zgo]

What ruined it for me was when I realised it liked to mark ac generators with "+ & -" like DC ones.

This was followed up by a plethora of beginners complaining because their Op Amp circuits worked perfectly in LT Spice, & became oscillators when built in real life.
I'm too old & cranky to have patience with dysfunctional things like that.

[eTobey]

Why are there all kinds of modern IC´s but not a bloody simple switch, that has been around since electricity was first discovered???
They copying issue was not an issues, since my VM did not copy the clipboard contents  .

I know i have to progam some things. That stupid switch does work somehow, it just wont turn off  .

I can now probe the base of may npn... i dont know why...

Another thing is: using M and m (with values) for the same thing.... so annoying... thankfully it isnt used often, but could ruin your day.

[langwadt]

What ruined it for me was when I realised it liked to mark ac generators with "+ & -" like DC ones.

nothing wrong with +/-, how else would you identify the phase ?

This was followed up by a plethora of beginners complaining because their Op Amp circuits worked perfectly in LT Spice, & became oscillators when built in real life.
I'm too old & cranky to have patience with dysfunctional things like that.

if you don't know what you are doing no tool is going to help ...

[langwadt]

Why are there all kinds of modern IC´s but not a bloody simple switch, that has been around since electricity was first discovered???
They copying issue was not an issues, since my VM did not copy the clipboard contents  .

I know i have to progam some things. That stupid switch does work somehow, it just wont turn off  .

I can now probe the base of may npn... i dont know why...

Another thing is: using M and m (with values) for the same thing.... so annoying... thankfully it isnt used often, but could ruin your day.

you have to define how you switch works

https://www.analog.com/en/technical-articles/ltspiceiv-voltage-controlled-switches.html

[iMo]

Do spend a week with basic stuff and you will know more about it.
Mega is "Meg" in LTSpice, milli is "m" in the LTSpice.
You need the model for the switch.
Do not complain - do learn something instead..

[vk6zgo]

What ruined it for me was when I realised it liked to mark ac generators with "+ & -" like DC ones.

nothing wrong with +/-, how else would you identify the phase ?

It is a single phase ac signal---in conventional equivalent circuits the only marking on the ac generator is a sine wave symbol.
 

This was followed up by a plethora of beginners complaining because their Op Amp circuits worked perfectly in LT Spice, & became oscillators when built in real life.
I'm too old & cranky to have patience with dysfunctional things like that.

if you don't know what you are doing no tool is going to help ...

If you mean the beginners & their attempts to produce workable circuitry, I concur, but if it is a "dig" at me, I do know, from practical experience what can happen with a conventional Op Amp circuit if it drives a reactive load.
The normal negative feedback used in such circuits can become positive feedback at a particular frequency, causing oscillation.

If a simulator does not allow for real world characteristics of standard circuits, it is incomplete.

[nctnico]

i wonder why everyone is using (it seems) ltspice. Its like working with a software from 199X, and i dont talk about the looks of it. Hotkeys that other programs have, ltspice does not use like undo for example. Or copying text from the result window does not work at all!

You could try Microcap 12 which is also free. It's user interface isn't the best either but IMHO much better compared to LTspice.

[eTobey]

I did not know, that i would need a masters degree, to simulate a quite simple circuit...

With the graph... i thought there was no use with scrollwheel, until i figured it out. BUT it is so bad, that it is useless, because it scolls only in tiny steps, and i havent found  a setting.

I would like to use google, but it has become as difficult to use as ltspice. I might just use it, when falstad fails.

[TimFox]

What ruined it for me was when I realised it liked to mark ac generators with "+ & -" like DC ones.

nothing wrong with +/-, how else would you identify the phase ?

It is a single phase ac signal---in conventional equivalent circuits the only marking on the ac generator is a sine wave symbol.
 

This was followed up by a plethora of beginners complaining because their Op Amp circuits worked perfectly in LT Spice, & became oscillators when built in real life.
I'm too old & cranky to have patience with dysfunctional things like that.

if you don't know what you are doing no tool is going to help ...

If you mean the beginners & their attempts to produce workable circuitry, I concur, but if it is a "dig" at me, I do know, from practical experience what can happen with a conventional Op Amp circuit if it drives a reactive load.
The normal negative feedback used in such circuits can become positive feedback at a particular frequency, causing oscillation.

If a simulator does not allow for real world characteristics of standard circuits, it is incomplete.

Nonsense:  the + and - terminals on an AC generator, as found in real Spice, are required in order for the phase of the signal at another node to make any sense whatsoever.
Generators and phase-sensitive voltmeters in the real world also need this definition.
Failure of a constructed circuit to agree with the Spice simulation is probably due to an incomplete or inaccurate device model for the op amp (which are actually intricate circuits), not the Spice simulation itself.

[langwadt]

What ruined it for me was when I realised it liked to mark ac generators with "+ & -" like DC ones.

nothing wrong with +/-, how else would you identify the phase ?

It is a single phase ac signal---in conventional equivalent circuits the only marking on the ac generator is a sine wave symbol.

that is incomplete and won't be work if you have more than one

This was followed up by a plethora of beginners complaining because their Op Amp circuits worked perfectly in LT Spice, & became oscillators when built in real life.
I'm too old & cranky to have patience with dysfunctional things like that.

if you don't know what you are doing no tool is going to help ...

If you mean the beginners & their attempts to produce workable circuitry, I concur, but if it is a "dig" at me, I do know, from practical experience what can happen with a conventional Op Amp circuit if it drives a reactive load.
The normal negative feedback used in such circuits can become positive feedback at a particular frequency, causing oscillation.

If a simulator does not allow for real world characteristics of standard circuits, it is incomplete.

everything is incomplete, what if someone builds the circuit with dodgy fake ebay opamps on a sketchy bread board with long wires and no decoupling?

[Feynman]

The user interface sucks for sure. But it never bothered me, really. I just accept it the way it is

[TimFox]

A clarification about the + and - terminals in Spice.
In the actual Spice file, which is line-oriented, there is a well-defined syntax.
For example, an AC generator with 1 V amplitude connected between nodes 10 and 20 is:
VIN    10   20   AC   1.0
where node 10 is the + node and node 20 is the - node in a graphic display of the circuit.
Similarly, a resistor will also have a + node and - node when the first entry starts with "R".

[SiliconWizard]

Rants are OK. We all rant sometimes. Use whatever tool you are comfortable with.

LTSpice if free and a great simulator actually.
Now its UI sucks a bit, but you get used to it. Most CAD software, even those that try to look "modern", have pretty, uh, "unique" UIs. Just the way it is.

If you can't use LTSpice for simulating a basic circuit, sorry to say this, but the problem is probably not with LTSpice.
Probably millions of people have been able to use LTSpice, I'm sure you will be too. Maybe have a look at the help, and a few tutorials.

[LazyJack]

I did not know, that i would need a masters degree, to simulate a quite simple circuit...

Actually, yes. In today's world of people trying to build stuff based on Istructables and fritzing drawings, lot then assume that electronics is simple. It is not. Spice can do more than simulate a led flasher, and in fact it was designed to accurately simulate complex circuits. Than comes with a steep learning curve and the need to know the limitations and requirements of the tool.
I agree, the gui may look old, but since the laws of physics haven't changed since Spice was developed, nobody felt the need to come up with a new version. I used Spice with the text based input and output long ago. Even that was perfectly usable, if one knew how to do that.

[eTobey]

I agree, the gui may look old, but since the laws of physics haven't changed since Spice was developed....

 I did not talk about the GUI. Its perfectly fine, to have an ugly GUI if it works. Rotating parts for example is not as intuitive, as i am used to. As said, it feels like 199x experience...

[james_s]

What's wrong with a 1990s experience? 90s software worked just fine, and Spice has been around much longer than that. It's a professional tool designed for people that know what they're doing, most professional tools are a bit clunky and not intuitive to a beginner, that's why toys like the Falstad simulator exist. Don't get me wrong, it's an impressive toy, I've used it myself, but it's really still just a toy. It's very easy to use but not nearly as powerful as Spice.

[eTobey]

What's wrong with a 1990s experience? 90s software worked just fine...

Yes wooden wheels work fine too. But I would like to have some rubber tube on it...

[n4u]

Dont forget ltspice is a numeric simulator - u need a good model to have proper behaviour. Even on paper when you using ideal or simplified elements you have wrong - non real life results.
You can generate ltspice files by scripts, or use a gui - just need to some practise.

[SiliconWizard]

I agree, the gui may look old, but since the laws of physics haven't changed since Spice was developed....

 I did not talk about the GUI. Its perfectly fine, to have an ugly GUI if it works. Rotating parts for example is not as intuitive, as i am used to. As said, it feels like 199x experience...

It doesn't. I don't think you get your references right.

While part of the GUI uses basic Windows GUI (menus, toolbars, dialogs), which is fine - unless you prefer this ugly toyish ribbon menu crap, which in itself is not even part of the Windows base controls, I think the problem you (and quite a few others) have is with the schematic editor, which implements a GUI that is not a "90s" GUI, but really more like a DOS-based UI, with heavy use of function keys, no sensible use of right click, the impossiblity of selecting objects just clicking on them, etc.

That part is not at all a "90s" GUI. GUIs of the 90s were perfectly capable of exposing anything we're used to today.
It's more that many CAD tools in general tend to suffer from the same thing, probably mostly because many of the most popular ones have had versions since DOS and have kept some of the UI for legacy reasons. I don't know the full history of LTSpice (just remember that it was initially called SwitcherCAD), but the author probably also had habits dating back to the very old days, and used to other CAD software.

Maybe just all a detail for you, but would explain james' reply.

Generally speaking, again many CAD tools, even recent versions, have weird quirks and UIs that are definitely not following the standard conventions of GUIs.

Regarding LTSpice in particular, a slight overhaul of the schematic editor and the waveform viewer would do the trick. It's not a huge endeavor.
But as with other CAD tools, I guess this has been put to low priority due to the fact that 1/ it's still usable and 2/ there are millions of users used to LTSpice's UI, and changing it would probably cause more friction than it would remove. And yes, that's the case with a lot of other software, and often explains an apparent lag in modernization. Just the way it is. It's very hard, if impossible, to please both your existing user base and new users.

[james_s]

Yes wooden wheels work fine too. But I would like to have some rubber tube on it...

What are you talking about? What exactly are 90s UIs missing that modern UIs have other than cosmetic fluff?

The fact that you don't know how to use a professional tool meant for professional engineers doesn't mean there's anything wrong with the tool.

[DimitriP]

The sad part about this conversation is that if LTSPICE was a program that was sold,  and a company was dependent on its "appeal" for continued sales, it would have been "revamped" a few times by now.
Like so many other "commercial" products that while still doing the same thing, the interface gets switched around for the sake of "change" in order to sell the new version and differentiate it from the "old" version.
I just know there are some of you out there that are super excited about windows 11  

[james_s]

I consider it a feature when software is stable, mature and rarely changes. I still use Office 2003 on my Windows machine, 20 years old now and it does way more than I need a word processor and spreadsheet to do. Best part is it doesn't have that stupid ribbon.

[DimitriP]

I consider it a feature when software is stable, mature and rarely changes. I still use Office 2003 on my Windows machine, 20 years old now and it does way more than I need a word processor and spreadsheet to do. Best part is it doesn't have that stupid ribbon.

So...there are two of us!

[iMo]

https://ltwiki.org/index.php?title=LTspice_Genealogy_-_The_Heritage_of_Simulation_Ubiquity

Btw I used to use the Spice (3G5 afaik) in 1987 (or 88) on my Atari520 (1MB dram), CLI only, no GUI. The binary size was around 350kB.. I wrote an app in Basic for generating nice graphs out of the text outputs later on..

[PlainName]

The fact that you don't know how to use a professional tool meant for professional engineers doesn't mean there's anything wrong with the tool.

Regardless of whether it's 'professional' or whatever, a tool works best when it is made to fit the user, not vice versa. Making it easier to use doesn't make it 'unprofessional' or a toy, it just makes things more efficient, less error prone and allows the user to focus on the result rather than the journey.

And, for that matter, just because user interface elements are new doesn't mean they are bad. Over time we learn what works well (and doesn't) and new ways to do things. Obviously, stuff made before these elements were available can't use them, but that doesn't automatically mean the old stuff is somehow better. Or that you have to suffer in order to be a 'professional' user.

[james_s]

And, for that matter, just because user interface elements are new doesn't mean they are bad. Over time we learn what works well (and doesn't) and new ways to do things. Obviously, stuff made before these elements were available can't use them, but that doesn't automatically mean the old stuff is somehow better. Or that you have to suffer in order to be a 'professional' user.

The reverse is also true, just because interface elements are new doesn't mean that they're better, or that older ones are bad. I'm not arguing that the older stuff is magically better, only that it is not automatically worse. LTSpice is a popular tool that works very well for its intended users, there's always room for improvement, but that will require somebody who thinks that improvement is worth the cost of doing it and the risk of breaking something else, which is virtually inevitable in software development.

[tchiwam]

I am warming up to Kicad + NGspice ...  Not perfect but somewhat usable and less frustration than typing everything or converting the netlist.

[nctnico]

I consider it a feature when software is stable, mature and rarely changes. I still use Office 2003 on my Windows machine, 20 years old now and it does way more than I need a word processor and spreadsheet to do. Best part is it doesn't have that stupid ribbon.

So...there are two of us!

No, three!

[Messtechniker]

Make that four!

[sb4]

I agree that the user interface is so non-standard that unless I use it daily, I have to relearn its quirks which takes time.  Example: I wanted to do a quick sim of a simple circuit as a proof-of-concept.  I first used the online version of Circuitlab which I've never used before.  In about 10 minutes I had an answer.  The interface is so intuitive that I was able to draw and simulate without referring to documentation.  I think the software also has "smarts" that helps get to an answer.

I really liked the pallet of "reference parts" on the left, which seem to be standardized parts that are typical.  One part I needed is a bridge rectifier module.  I have not yet found such a part in LTspice as installed.  It was easy to place parts, connect them, and run a basic transient simulation.

Because Circuitlab requires a subscription to save your circuits, I decided to do the same thing with LTSpice, which I used extensively years ago.  Immediately I hit frustration as I could not remember the quirky GUI.  I wanted to select a part to rotate it, but there is no generic select tool.  You need to use the "move" hand-shaped cursor, and then press ctrl-R.  I doubt I would have discovered that by trial and error, I had to google.  The lack of a general select tool constantly stumps me.  You have to use a "scissors" tool to delete a part, etc.  I am also flummoxed by the lack of scroll bars on the schematic window.  You can zoom in and out, but your schematic may drift out of view.  Until I know better, I end up zooming out and trying to move the entire schematic into the center of the window, then zooming back in. 

Selecting parts can be daunting since rarely used parts and popular parts are lumped into long lists.  Very often we just want to grab a typical reference part with wide specs to check proof-of-concept of a circuit.  There may be a way to set that up in LTspice, but it doesn't jump out at you.  Circuitlab just has a nice common list of parts visible from the get-go.

I have a lot of confidence that LTspice simulations are well designed, fast, and accurate, though you may have to research how to tweak parameters for best performance.  So I'm mainly complaining about the GUI.  I'm aware that the guy who has been maintaining LTspice has left and now is maintainint QSpice, which is his complete rewrite of LTspice and supposedly has much better code.  On first look, the GUI isn't any more friendly.  However, perhaps now we can put in requests for improvement to the LTSpice GUI and get more response.  An alternate GUI option like Circuitlab's would be my suggestion.  Keep the original, but have an option to select the alternate.

[Doctorandus_P]

I understand "professionals" put up with all sorts of quirkiness, as long as they get paid to spend time on such software. But for me as a hobbyist I could never get used to ltspice. I also don't like having to run it under wine.

The integration of ngSpice in KiCad is getting better each year though. A big advantage for me is that I don't have to get used to how most of the program (schematic entry) works, because I already know KiCad, and it's schematic entry is also pretty intuitive. But using ngSpice has it's speed bumps too. Getting models that are compatible is a big nuisance for example. Another (small) nuisance is pin remapping. For some reason, pin numbers in spice models do not always agree with pin numbers on IC packages. There is a pin remapping function built in, but if your simulation does not run, then it is just one extra thing that adds to your headaches. Especially for beginners getting a simulation to run is a bit of a challenge.

I don't use circuit simulation much, but if I do, it is KiCad / ngSpice. Partly because I already have it installed, it's one of the very few up to date packaged that run natively under Linux, and it's Open Source, which is also an important factor for me.

[QOTF-Alexi]

I've tried to switch to the simulation in Altium Designer, but it's honestly quite terrible if you don't have your own models. SIMetrix/SIMPLIS Elements is free to use, but you do get a popup every time you open it, begging you to buy the full thing. Works fine though. But you can't just place a probe and keep it there forever, since the graph does not seem to update when you re-run a simulation when you changed, say, a resistor value. It would probably work better if I had the full edition, since that integrates into AD with a (to those with a student license free) extension. But as a hobbyist user it's not worth it buying that software.

[Zero999]

I consider it a feature when software is stable, mature and rarely changes. I still use Office 2003 on my Windows machine, 20 years old now and it does way more than I need a word processor and spreadsheet to do. Best part is it doesn't have that stupid ribbon.

So...there are two of us!

No, three!

Yes, I wish developers wouldn't change the GUI, just to appar trendy or pretend they've improved the software to encourage sales. One of the reasons why I use LibreOffice is so I can escape the crappy Ribbon interface of MS Office. Although I'm fine with the LTSpice GUI, I can sympathise, mainly because I hate MS Office.

F9 is undo. There are dozens of various switches, you have to download and install libraries.
https://groups.io/g/LTspice
LTSpice is not an interactive toy, you have to program the behavior of the switches.
When you name a wire "base" you can easily probe it..
I never had a problem with copy/paste something off the results windows in LTSpice..
Get a little bit familiar with the LTSpice, it is a great tool..

The downside is, opening the file on another install without the switch symbols will break the schematic.

I prefer to use the current controlled switch. Here's an example of using a voltage source to control the switch. The internal resistance is set to 1R and voltage 1V, so the short circuit current is 1A. The CSW model has been set so it transitons smoothly, which can help to avoid convergence errors.

[JPortici]

Yes, I wish developers wouldn't change the GUI, just to appar trendy or pretend they've improved the software to encourage sales. One of the reasons why I use LibreOffice is so I can escape the crappy Ribbon interface of MS Office. Although I'm fine with the LTSpice GUI, I can sympathise, mainly because I hate MS Office.

i see you haven't installed LibreOffice 24 then

(yes, it's optional - for now. - but it's already the default)

re: thread i greatly appreciated the UI revamp in the newer LTSpice 24, works much better for me, with all the changes in shortcuts and feel i never bothered making

[shapirus]

The integration of ngSpice in KiCad is getting better each year though. A big advantage for me is that I don't have to get used to how most of the program (schematic entry) works, because I already know KiCad, and it's schematic entry is also pretty intuitive. But using ngSpice has it's speed bumps too. Getting models that are compatible is a big nuisance for example. Another (small) nuisance is pin remapping. For some reason, pin numbers in spice models do not always agree with pin numbers on IC packages. There is a pin remapping function built in, but if your simulation does not run, then it is just one extra thing that adds to your headaches. Especially for beginners getting a simulation to run is a bit of a challenge.

Another big source of frustration with ngspice is its very, very poor ability to converge with anything even remotely complex (in transient sims). Timestep too small, my ass. And try to guess where the problem exactly is, it will never tell you. First it's one branch, often totally unrelated (e.g. not even energized at the time), then you adjust a sim parameter or a value of some capacitor or whatever, and it fails again, but this time complaining for a totally different branch.

Sometimes I have to resort to setting reltol to as high as 0.2 (!) to finally make it pass a certain stubborn point. Sometimes even that doesn't help. Fast transients are a problem? Yes they can be. Good luck finding where it might be when you have a dozen logic gates and whatnot. And the funny thing is that it often works when you simulate them separately as individual functional blocks, but fails when you enable all of them at once -- and it never tells you why, at least in terms that can be understood by someone who has no experience of writing their own spice engine as part of their university course.

Sometimes it's possible to guess what's going on if it fails at a point when a certain event is expected to happen, but sometimes it fails in the middle of nowhere when everything should be stable or changing slowly.

To put it in a different perspective, it's a PITA when you try to use it to simulate whole circuits. It's better when you can divide your whole circuit into separate blocks and simulate them one by one. But if you ask me, that's nothing else than just a workaround for a poorly working software. Both good and bad software can fail, I'm not blaming it for failing. But the difference between good and bad software is how they fail. Good error messages that make troubleshooting easy are essential.

In its present state, ngspice, even though it's actually pretty usable, with some limitations, still looks more like an academical project developed by a team of scientists (and it's good at that!) who don't care about its suitability for practical real world usage.


p.s. on topic... LTSpice? Seem better suited for real life, even though the UI is weird. Much faster than ngspice. Huge number of available models. Too bad there's no native integration with kicad. I wonder if it's not as brittle in terms of convergence on complex circuits as ngspice, haven't had much experience with it.

[Zero999]

Yes, I wish developers wouldn't change the GUI, just to appar trendy or pretend they've improved the software to encourage sales. One of the reasons why I use LibreOffice is so I can escape the crappy Ribbon interface of MS Office. Although I'm fine with the LTSpice GUI, I can sympathise, mainly because I hate MS Office.

i see you haven't installed LibreOffice 24 then

(yes, it's optional - for now. - but it's already the default)

No, I haven't.

I'm not entirely against the concept of tabbed toolbars. It's just how it has been implemented in MS Office and the fact they changed it, without the ability to go back, for no reason.

I suppose LibraOffice will have to change to make it more familiar to MS Office users. If it's bad, then I can disable it. If they make it mandatory, I can just use the older versons and no doubt it'll annoy enough people, someone will fork it and create a version with the traditional UI.

re: thread i greatly appreciated the UI revamp in the newer LTSpice 24, works much better for me, with all the changes in shortcuts and feel i never bothered making

That's how changes in the UI should be done: introduce improvements and features, without revamping everything, just because.

[Rafiki]

I suppose LibraOffice will have to change to make it more familiar to MS Office users. If it's bad, then I can disable it. If they make it mandatory, I can just use the older versons and no doubt it'll annoy enough people, someone will fork it and create a version with the traditional UI.

You can always use the other branch which evolved from StarOffice (as LibreOffice did) - Apache OpenOffice. AOO does not update that often which is sometimes advantages sometimes disadvantages. But the AOO developer obviously don't follow the crowd with these ribbon sh...  but still use standard CUA instead.

[temperance]

@ eTobey

https://www.eevblog.com/forum/testgear/sds800x-hd-featureimprovment-disscusions/75/

Why is it that you are bashing everything? In fact we are all pretty spoiled.

-Free circuit simulators and not just toys.
-Ultra low cost but extremely capable micro controllers
-Transistors, op amp, and just about anything you can imagine for peanuts
-Full fledged in circuit emulators for €10
-Programmable logic in all flavors for peanuts including extremely capable tools
-Free CAD software

You want people of my age to write you rants about the tools we played with about 25 years ago? Of course I hated erasing EPROM's if it didn't work again and again. Was the EPROM at fault? No, not at all. I felt more frustration about my own capabilities and shortcomings and I still do so today. If something doesn't work or doesn't perform as I think it would, I rather question myself and investigate the problem and search for answers in a meaningful way. Researching a problem has become very easy with the internet as a resource. This statement doesn't state all manuals and everything is always correct. Manuals, app notes,...are all written by people writing from their own perspective and they make mistakes.

If remembering Ctrl+r frustrates you then maybe you are pursuing the wrong hobby or career if putting in your own effort to understand something is too much for you.

EDIT: some LT spice tutorials: (the links point to playlists on YT)

A tutorial by the man behind LTspice himself:


FEZ Electronics


Does it still disappoint you after watching all this?


EDIT:

Like so many other "commercial" products that while still doing the same thing, the interface gets switched around for the sake of "change" in order to sell the new version and differentiate it from the "old" version.

Confirmed, some pretty expensive software just rearrange old bugs in a different way.

[SiliconWizard]

I personally don't care about the UI, LTSpice is free and the fastest free Spice simulator out there. It was already faster on most simulations than ngspice before version 24, but with the speed improvements of v24, it just beats its pants badly in terms of sim speed, to the point of making ngspice extremely frustrating.

I still use ngspice when LTSpice doesn't cut it, but clearly its simulation speed is becoming a problem.

I don't expect a Spice simulator to be a nice and full-fledged schematic editor, but to each their own. LTSpice can also take Spice text directly, and I believe it can be run on the command-line as well, although I've rarely used it that way.

[amaschas]

I will be honest, as a hobbyist LTSPice is totally impenetrable. I've tried it a half dozen times, given up and just constructed my circuit on a breadboard and used a oscilloscope to figure out what was going on.

[Wolfgang]

Some side facts about LtSpice.

- it was (and is) a free tool, once developped by Mike Engelhard at Linear tech to support the design of switching power supplies using Lts IC portfolio.
- LtSpice (once SwitcherCad) is more than 20 years old.
- Focus was on convergence and stable math, not so much on a fancy user interface.
- The USP of LtSpice is speed. In fact, it creates machine language programs from you spice plans and runs them im parallel on Intel CPUs. Normally beats other spices by a factor of 5..100.
- The inventor of LtSpice is a Klingon that has no compassion for beginners. I guess that people complaining about the GUI and some Spice handling issues can just go to hell (he has put this more politely).
  Read the manual, search the net, learn the ropes, look at a lot of examples and user forums - ... only *then* write him an email. He *is* responsive is your problem is something "real", however.
- There are a lot of "toy" spices around. I personally used 5Spice quite some time ago.
  Simple, easy to use, better graphics - but it was slow, did not converge in many cases, did not allow model creation, and was not even free ... crippleware compared to LtSpice.
  I used foul language a lot for about a week when I switched to LtSpice, but in the end, wow, what an improvement!

IMHO, you are out of luck if your Spice needs are serious. LtSpice downloads *per day* are a few thousands, more any the total of any other spices combined. LtSpice *owns* the market,
so you need to get used to them instead of LtSpice will change to what you want, sorry.

[tszaboo]

Some side facts about LtSpice.

What you describe is complacency.
I never liked LTSpice. It's somehow simultaneously too simple and too complicated. The whole electronics simulator market feels like 1990s with bad UI, incompatibilities, software written in archaic languages, bad scripting, bad output formats. Freeware that is operated as a walled garden.
Nobody cares how much time a simulation takes. What I care about is how much time completing a task takes, and that's a long time because the software needs serious UI improvements.

[shapirus]

I never liked LTSpice. It's somehow simultaneously too simple and too complicated. The whole electronics simulator market feels like 1990s with bad UI, incompatibilities, software written in archaic languages, bad scripting, bad output formats. Freeware that is operated as a walled garden.
Nobody cares how much time a simulation takes. What I care about is how much time completing a task takes, and that's a long time because the software needs serious UI improvements.

That's just how it goes. You have to be a scientist to create and maintain software like this. But when you're a scientist, you don't care about that earthly nonsense such as UI or fancy bleeding edge technologies.

Besides, just remember when spice was first created. We must feel lucky that netlists are at least plain text files and not some binary code.

[Bud]

Sorry but this is BS. Take Electro Magnetic simulators - they employ much more complex science but also have decent UI and plotting capabilities.

[Wolfgang]

Some side facts about LtSpice.

What you describe is complacency.
I never liked LTSpice. It's somehow simultaneously too simple and too complicated. The whole electronics simulator market feels like 1990s with bad UI, incompatibilities, software written in archaic languages, bad scripting, bad output formats. Freeware that is operated as a walled garden.
Nobody cares how much time a simulation takes. What I care about is how much time completing a task takes, and that's a long time because the software needs serious UI improvements.

Yup. They not feel the need to change a lot for casual users. They are undisputed number one, so ... Maybe YOU can write a better LtSpice, they wont. Much luck, BTW.

[Wolfgang]

Yeah, agreed. But these people are not monopolists, and EM software is quite costly. LtSpice was more or less a one man show (Mike) from a guy with a physics background, not from graphics design.
I must say that it is quite remar.kable what he achieved with a free tool that became the undisputed number one in a whole industry.

If you dont like it, dont complain, do something better.

[DimitriP]

Some side facts about LtSpice.

What you describe is complacency.
I never liked LTSpice. It's somehow simultaneously too simple and too complicated. The whole electronics simulator market feels like 1990s with bad UI,   incompatibilities , software written in archaic languages, bad scripting, bad output formats. Freeware that is operated as a walled garden.
Nobody cares how much time a simulation takes. What I care about is how much time completing a task takes, and that's a long time because the software needs serious UI improvements.

You either learn how to ride a bicycle, or you dont. You don't blame the "interface" or  gravity.

[PlainName]

You either learn how to ride a bicycle, or you dont. You don't blame the "interface" or  gravity.

Wrong analogy. It is more like the bicycle doesn't have a seat but just the bare end of the upright tube.

[shapirus]

Sorry but this is BS. Take Electro Magnetic simulators - they employ much more complex science but also have decent UI and plotting capabilities.

Well, we need to compare apples to apples. I have zero idea about the EM simulators you mentioned: are there any that are free (like LTSpice) and FOSS (like ngspice), developed pretty much by enthusiasts?

Otherwise, we can compare them with expensive commercial circuit simulators that sometimes have quite decent UI, easy learning curve and work well consistently enough. These apparently can afford (and see the necessity) to spend at least some resources to adapt the raw number crunching backend to the unprepared end user's expectations.

[Wolfgang]

You either learn how to ride a bicycle, or you dont. You don't blame the "interface" or  gravity.

Wrong analogy. It is more like the bicycle doesn't have a seat but just the bare end of the upright tube.

I have never seen a single case where such a bike became the undisputed industry standard. Maybe the comparison is flawed. 

[shapirus]

I have never seen a single case where such a bike became the undisputed industry standard. Maybe the comparison is flawed. 

Well, something becoming an industry standard doesn't automatically mean that it's good. One example is imperial units.

[DimitriP]

You either learn how to ride a bicycle, or you dont. You don't blame the "interface" or  gravity.

Wrong analogy. It is more like the bicycle doesn't have a seat but just the bare end of the upright tube.

The analogy works no matter what.
As long as there are people capable of riding it.....you either learn how to ride it , or you dont.

[tszaboo]

Some side facts about LtSpice.

What you describe is complacency.
I never liked LTSpice. It's somehow simultaneously too simple and too complicated. The whole electronics simulator market feels like 1990s with bad UI, incompatibilities, software written in archaic languages, bad scripting, bad output formats. Freeware that is operated as a walled garden.
Nobody cares how much time a simulation takes. What I care about is how much time completing a task takes, and that's a long time because the software needs serious UI improvements.

Yup. They not feel the need to change a lot for casual users. They are undisputed number one, so ... Maybe YOU can write a better LtSpice, they wont. Much luck, BTW.

This is called https://en.wikipedia.org/wiki/Appeal_to_accomplishment fallacy.
In case you are wondering, fallacies are bad way of arguing.

[Wolfgang]

Some side facts about LtSpice.

What you describe is complacency.
I never liked LTSpice. It's somehow simultaneously too simple and too complicated. The whole electronics simulator market feels like 1990s with bad UI, incompatibilities, software written in archaic languages, bad scripting, bad output formats. Freeware that is operated as a walled garden.
Nobody cares how much time a simulation takes. What I care about is how much time completing a task takes, and that's a long time because the software needs serious UI improvements.

Yup. They not feel the need to change a lot for casual users. They are undisputed number one, so ... Maybe YOU can write a better LtSpice, they wont. Much luck, BTW.

This is called https://en.wikipedia.org/wiki/Appeal_to_accomplishment fallacy.
In case you are wondering, fallacies are bad way of arguing.

Its not my program, I am just diagnosing what is going on. Wisdom is to change what needs to be changed, accept what cannot be changed and having the good judgement to keep the alternatives apart. In case of LtSpice ...

[DimitriP]

In case of LtSpice ...

Today it's LTSPICE, tommorow HPAK/Siglent/Tek/Rigol.Unit-T  will put some button or menu choice in the "wrong" place, the probe is going to be too long, too short, too expensive, the wrong color or have the wrong cable length...every so often we become entitled to every TD&H opinion  of how someone else should have gotten something done and the correct speed at which the Earth should really be orbiting the Sun.

It's a never ending story. There is even a song to go with it. Dunno if there is a T-Shirt.
  

[mikerj]

Some side facts about LtSpice.

What you describe is complacency.
I never liked LTSpice. It's somehow simultaneously too simple and too complicated. The whole electronics simulator market feels like 1990s with bad UI, incompatibilities, software written in archaic languages, bad scripting, bad output formats. Freeware that is operated as a walled garden.
Nobody cares how much time a simulation takes. What I care about is how much time completing a task takes, and that's a long time because the software needs serious UI improvements.

Yup. They not feel the need to change a lot for casual users. They are undisputed number one, so ... Maybe YOU can write a better LtSpice, they wont. Much luck, BTW.

This is called https://en.wikipedia.org/wiki/Appeal_to_accomplishment fallacy.
In case you are wondering, fallacies are bad way of arguing.

Many, many thousands of people use LTSpice daily without a problem. If you are unable to use it despite a vast wealth of information and libraries freely available, perhaps this says more about you than the application?  You could always ask for a refund I guess 

[shapirus]

Many, many thousands of people use LTSpice daily without a problem.

Another many thousands, on the other hand, use it with problems: yes it gets the job done, but it is the same as using any other tool that's awkward and inconvenient.
The fact that it gets the job done and that one can get comfortable with it despite its, uh, pecularities, does not disprove its drawbacks.

Here's a correct bike analogy:

If you are

Don't forget that we're discussing LTSpice, not its users. Especially not a particular user. Personal arguments and attacks aren't necessary.

[tszaboo]

Many, many thousands of people use LTSpice daily without a problem. If you are unable to use it despite a vast wealth of information and libraries freely available, perhaps this says more about you than the application?  You could always ask for a refund I guess 

This one is called ad hominem. https://en.wikipedia.org/wiki/Ad_hominem In case you are wondering it's an even lower tier argument style.
Oh and also https://en.wikipedia.org/wiki/Argumentum_ad_populum

[CatalinaWOW]

There is a conundrum here.  Spice of any flavor is a tool to observe circuit performance.   Just as an oscilloscope is.  You should always use the best tool for the job.  Spice was developed to observe circuit that are hard to observe with other tools.  Integrated circuits where probing ranges from difficult to impossible. 

No model is ever perfect.  And it takes experience, both success and failure to learn when a model is good enough. 

So now you have a beginner, trying to learn the modeling program.  It would be stupid to model such a simple circuit if that were the end goal.  It is the wrong tool.  Just build it and measure it. But the end goal is to model those hard to measure things.  So all the foibles of both the software interface and modeling are being fought while comparing to an oscilloscope.

Hang in there.  Learn the foibles and you will be rewarded.  The process would be frustrating even with the zoomiest new interface.

[Someone]

The process would be frustrating even with the zoomiest new interface.

Having an interface consistent with the platforms UI guidance would be nice, or at least consistent in time. Go and use the OSX version of LTspice and then explain why it doesnt match either the OS style, or the windows LTspice controls.

When the "standard" OS shortcuts aren't used, yet not mapped to anything at all. That's some pathological design.

[Wolfgang]

I absolutely agree that the GUI of LtSpice is gook and nonstandard. The problem is that LtSpice had and has so little competition so that the GUI was never a priority.
Its free, but not open source so attaching a better GUI to the otherwise quite brilliant numerics core is no option, unfortunately.
So - you may complain, even curse, whatever, but all Spicers have to live with this for the foreseeable future, sorry.

PS: To my knowledge Mike Engelhard is now writing a new Spice at Quorvo. You dont hear much of it, though, and downloads seem to be limited to the US.

[DimitriP]

........
PS: To my knowledge Mike Engelhard is now writing a new Spice at Quorvo. You dont hear much of it, though, and downloads seem to be limited to the US.

Oh good...that will delay further whining about how he did the interface wrong

[Wolfgang]

........
PS: To my knowledge Mike Engelhard is now writing a new Spice at Quorvo. You dont hear much of it, though, and downloads seem to be limited to the US.

Oh good...that will delay further whining about how he did the interface wrong

Yeah, unfortunately. We could send a full catalog of ancient greek and roman rhetorics to Lt (now AD) and see if that impresses them. 

[Gerhard_dk4xp]

PS: To my knowledge Mike Engelhard is now writing a new Spice at Quorvo. You dont hear much of it, though, and downloads seem to be limited to the US.

Hä??   I did download it to .de.

<    https://forum.qorvo.com/c/qspice/9    >  my shortcut to the forum.

regards, Gerhard

[Wolfgang]

Just tried again, but the registration mail supposed to be send by them never arrived.

[Gerhard_dk4xp]

I just did an update to state of $NOW and it works for me.

[Wolfgang]

Did not work again, maybe t-online mail is blacklisted by them. I wrote to Quorvo support and they sent me a direct download link, and this one worked.
Thanks anyway
  Wolfgang

[Nominal Animal]

I've thought about creating a Python 3 + Qt 5 interface for ngspice (open source).  That is possible only because ngspice provides a command line/file-based interface.  Many applications, including Altium Designer 19 and 20, and KiCad 7 and later, do support it already.

KiCad 7 and later have pretty good interface for ngspice, but it could be easier.  In particular, I miss the ease of creating new symbols I have in EasyEDA; and I'd prefer an easy to manage library format, preferably copying both the symbols and the NGSPICE/PSPICE/LTSPICE snippets, instead of file references, for ease of maintenance.  And being able to run more than one simulation (based on different schematics) at a time, of course.

Alas, my own user interface preferences seem weird to others, so doing that just for myself isn't worth it.  I can live with KiCad's oddities and occasional crashing; I'm just a hobbyist on the electronics side.  If I were to actually create such an application, I'd need to see and understand the actual workflows of a few different professionals and a couple of hobbyists, as I always use need that kind of information to construct proper user interfaces (except for examples and throwaway demos I've shown in other threads, of course).  Yet, professionals are hung up on LTspice, and don't seem interested in ngspice at all.

[Wolfgang]

Yup. Speed, numerical stability and accuracy as well as convergence are much more important for a pro than GUI issues. You can get along with a weird user interface,
but not with lack of results or false predictions.

[tooki]

The process would be frustrating even with the zoomiest new interface.

Having an interface consistent with the platforms UI guidance would be nice, or at least consistent in time. Go and use the OSX version of LTspice and then explain why it doesnt match either the OS style, or the windows LTspice controls.

When the "standard" OS shortcuts aren't used, yet not mapped to anything at all. That's some pathological design.

And in this case, we know for a fact why it is this way (with the Mac version being even less Mac-like than the Windows version!!): because the developer arrogantly believes that he knows the one “right” way software should be used, platform conventions be damned. He expressed contempt at users of the Windows version using the toolbar and menus, rather than right-click menus (his One True Way), so when he later made the Mac version, he didn’t provide those, to force people to use right-click menus. This is 180° contrary to the Mac way (the platform’s human interface guidelines expressly say that right-click menus are strictly a supplemental way to access commands*). As a former usability engineer this is a textbook example of a UI designed by engineer who has zero understanding of how normal users think, and basically treats them — and any usability experts who try to nudge them in the right direction — with contempt.

I’m hoping that, now that he’s left the company, LTspice will end up in the hands of developers who are user-centric.

*Yes, I am fully aware that Apple itself started ignoring many of its own guidelines, and I’m as irritated about this at least as much as when third party developers do it. (And I’m not alone in this sentiment.)

[Nominal Animal]

Speed, numerical stability and accuracy as well as convergence are much more important for a pro than GUI issues.

Have you actually compared LTspice and ngspice performance, or this based on the old "because LTspice is the market leader, it must be better than the competitors" fallacy?

(While I am only a hobbyist in electronics, I've worked on simulators and HPC quite a lot, more on the development side than on the end user side.)

[shapirus]

Have you actually compared LTspice and ngspice performance, or this based on the old "because LTspice is the market leader, it must be better than the competitors" fallacy?

I have. LTSpice was much, like several times at least, faster than ngspice. This is only anecdotal evidence, though, so take it with a grain of salt. Proper testing would require setting all simulation parameters to the same values (because defaults may differ), making sure the models are as close as possible, etc.

Ngspice can be very fast, too. Just relax the tolerances, and in practice they can be relaxed quite significantly, almost to the levels that seem unreasonable, and it'll still deliver correct simulation results, only maybe somewhat less precise in some situations, or it may show some artifacts that can be ignored, once you know they aren't real.

[Nominal Animal]

LTSpice was much, like several times at least, faster than ngspice.

Now that does not surprise me, as ngspice uses a single thread per simulation.  It was the numerical stability, accuracy, and convergence claim that surprised me and made me suspicious.

That said, in addition to being single-threaded only, it is not a drop-in replacement LTspice nor meant to be one.  However, being supported in Altium Designer, Eagle, DipTrace, and other commercial software is an indicator that at least some professionals do use it already.

Anyway, this kind of brand loyalty is exactly why I nowadays shirk away from professional software development: to do it properly, one must invest more in marketing and branding than the development itself.

[mawyatt]

Sorry but this is BS. Take Electro Magnetic simulators - they employ much more complex science but also have decent UI and plotting capabilities.

Sorry but this is BS, models used in EM simulations are nowhere near as complex or involved as some semiconductor models utilized in Spice and its' various derivatives. It can take many man-years to develop a single semiconductor transistor model with sufficient fidelity to bet a complex and expensive IC design on. If you doubt this just take a look at the much older Mextram, HiCum, PSP (Pen State Phillips) BSIM 6 models just to name a few general purpose ones utilized in IC design.

Take note of the parameters involved, and image what the proprietary models that are utilized in SOTA semiconductor design today (@ 3nm), considering that modern SOTA semiconductor designs involve EM simulations within the overall framework of the semiconductor device itself, so the EM simulations are a small subset of a much more involved and complex structure which is dealing with atomic level details as well as macro level device details.

Best,

[Wolfgang]

LTSpice was much, like several times at least, faster than ngspice.

Now that does not surprise me, as ngspice uses a single thread per simulation.  It was the numerical stability, accuracy, and convergence claim that surprised me and made me suspicious.

That said, in addition to being single-threaded only, it is not a drop-in replacement LTspice nor meant to be one.  However, being supported in Altium Designer, Eagle, DipTrace, and other commercial software is an indicator that at least some professionals do use it already.

Anyway, this kind of brand loyalty is exactly why I nowadays shirk away from professional software development: to do it properly, one must invest more in marketing and branding than the development itself.

There are some YT videos where Engelhard explains why and how LtSpice has superior math compared to other Spices.

[Wolfgang]

Sorry but this is BS. Take Electro Magnetic simulators - they employ much more complex science but also have decent UI and plotting capabilities.

Sorry but this is BS, models used in EM simulations are nowhere near as complex or involved as some semiconductor models utilized in Spice and its' various derivatives. It can take many man-years to develop a single semiconductor transistor model with sufficient fidelity to bet a complex and expensive IC design on. If you doubt this just take a look at the much older Mextram, HiCum, PSP (Pen State Phillips) BSIM 6 models just to name a few general purpose ones utilized in IC design.

Take note of the parameters involved, and image what the proprietary models that are utilized in SOTA semiconductor design today (@ 3nm), considering that modern SOTA semiconductor designs involve EM simulations within the overall framework of the semiconductor device itself, so the EM simulations are a small subset of a much more involved and complex structure which is dealing with atomic level details as well as macro level device details.

Best,

The problem with complicated device models covering almost all areas of operating conditions is the extraction of the a lot of parameters from measurements. This is an absolute orgy of a huge data collection and curvefitting effort. In the end, you have a super model valid just for the part you measured. When you look at the strays of, e.g., transistor beta between devices this raises the general questions about the benefit of "overparametrized" models that only work for a single specific device. What you rather want is a robust design that can work with devices within datasheet value ranges. 

[shapirus]

That said, in addition to being single-threaded only, it is not a drop-in replacement LTspice nor meant to be one.

Well, once you make your product public, it starts to live a bit of its own life :).

Naturally, people (or at least myself!) will want it to be as capable as possible regardless of its original goals: fast, well-converging, accurate, and supporting as many models of varying syntax as possible. In other words, be well suited for real life applications. Currently it's far from ideal in that regard, especially out of the box with default settings, but it's being actively developed, so hopefully it'll become a much more mature tool eventually, especially considering the Kicad's native integration.

[PlainName]

Sorry but this is BS. Take Electro Magnetic simulators - they employ much more complex science but also have decent UI and plotting capabilities.

Sorry but this is BS, models used in EM simulations are nowhere near as complex or involved as some semiconductor models utilized in Spice and its' various derivatives. It can take many man-years to develop a single semiconductor transistor model with sufficient fidelity to bet a complex and expensive IC design on. If you doubt this just take a look at the much older Mextram, HiCum, PSP (Pen State Phillips) BSIM 6 models just to name a few general purpose ones utilized in IC design.

Perhaps this is the problem: the workings of the model isn't separated from the interface to it?

AFAIK, the model complexity has zero to do with the GUI. All that does it let you place things here, change stuff there, join this to that. Shouldn't the models be backend black boxes? The complexity of their internals should be a non-issue in relation to what key does copy, how the schematic is zoomed, making the text always be upright when a symbol is rotated, etc.

[mawyatt]

The problem with complicated device models covering almost all areas of operating conditions is the extraction of the a lot of parameters from measurements. This is an absolute orgy of a huge data collection and curvefitting effort. In the end, you have a super model valid just for the part you measured. When you look at the strays of, e.g., transistor beta between devices this raises the general questions about the benefit of "overparametrized" models that only work for a single specific device. What you rather want is a robust design that can work with devices within datasheet value ranges.

The later part of our career was involved with SOTA IC design and processes, and believe me there's lots more to a modern SOTA device model at the IC level that just curve fitting a bunch of data. Most modern process models are highly semiconductor physics based, some completely, and some employ physics based and "curve fitted" data behavioral type models.

Over 2 decades ago we were working with very complex models in SOTA SiGe BiCMOS processes which included proximity and local neighbor effects, these effects were not limited to just electrical/fields, but included sophisticated multiple time constant thermal effects (BTW we started doing time domain thermal effects in Spice in the 80s!!). If you've ever been involved with detailed simulator behavior (we had to design our own simulators way back in the beginning silicon RFIC era as nothing was available at that time), you'll appreciate the enormous computational burden these models impose. However you'll happily pay that price as you may have a $20M SOTA IC design that's totally influenced by those very models and the folks that developed them

IC design mistakes, changes, mods, rewires, updates, tweaks and so on requiring a "respin" with long delays (often 4 months or more) are quite expensive and career limiting the IC design world, and one is almost totally dependent on these very models for a successful chip design and career!!

Lots more than just "curve fitting" a bunch of data is required for SOTA modern semiconductor models

Best,
 

[mawyatt]

Sorry but this is BS. Take Electro Magnetic simulators - they employ much more complex science but also have decent UI and plotting capabilities.

Sorry but this is BS, models used in EM simulations are nowhere near as complex or involved as some semiconductor models utilized in Spice and its' various derivatives. It can take many man-years to develop a single semiconductor transistor model with sufficient fidelity to bet a complex and expensive IC design on. If you doubt this just take a look at the much older Mextram, HiCum, PSP (Pen State Phillips) BSIM 6 models just to name a few general purpose ones utilized in IC design.

Perhaps this is the problem: the workings of the model isn't separated from the interface to it?

AFAIK, the model complexity has zero to do with the GUI. All that does it let you place things here, change stuff there, join this to that. Shouldn't the models be backend black boxes? The complexity of their internals should be a non-issue in relation to what key does copy, how the schematic is zoomed, making the text always be upright when a symbol is rotated, etc.

We weren't disputing the GUI interface but the statement about EM simulation complexity, and why we highlighted such.

Agree the GUI is totally disconnected from the simulation engine and models. However, treating a complex semiconductor model as a "blackbox" is risky, as most seasoned IC designers are quite knowledgable and often involved with the model development and behavior.

One must realize that the models aren't prefect representations of the device, and simulations often mislead or "lie" about the results and require a competent designer to recognize such. Recall cases where we discovered a non-realistic beta (over 1100) in a SiGe bipolar device under certain operating conditions, or the discontinuity in the second derivative of channel conductance with channel current direction change in the popular BSIM CMOS model, or a violation of charge conservation in another CMOS model.

Also, as semiconductor model complexity grows, so do the non-convergence events and simulation hang ups. Having "inside" information on the models involved can help alleviate such and/or create work arounds!!

Best,

[Nominal Animal]

Perhaps this is the problem: the workings of the model isn't separated from the interface to it?

Yes, I believe so.

Unfortunately, that choice itself is a huge divide in the software world.  We have the integrated framework approach, and we have the modular minimalism approach.  Even talking about this I risk starting a flamewar.

(Don't mistake my choice of mascot as an ideology or zealotry.  I've worked with both proprietary and open source code, and signing NDAs has never been a problem for me.  What I do trust, is the test of time and use cases, rather than the opinion of some "authority", though.)

AFAIK, the model complexity has zero to do with the GUI.

Exactly.

If the user interface was separated from the actual simulator, other schematic capture programs could use it as a simulator, and different user interfaces for the same simulator to support different workflows.

There are some YT videos where Engelhard explains why and how LtSpice has superior math compared to other Spices.

Mike Engelhardt is the author of LTspice, and the only one with access to its sources.  I'm very hesitant to believe any authors word as to why their solution is superior, if I cannot verify it for myself.

This is not a slight on Engelhardt, mind you.  I apply the same, strictly, to my own solutions and even examples and suggestions.  I never just claim something; I always show how to verify the claim for yourself.

Agree the GUI is totally disconnected from the simulation engine and models.

Except in the case of LTspice, where they are inseparable, even though we have the exact information that the simulation engine needs.

The practical result of this is that LTspice only runs on Windows (7-10) and MacOS (10.15+) on x86 and x86-64, and has a single user interface.


This sidetrack started because I mentioned I've seriously considered writing my own (portable) schematic capture and symbol editor on top of ngspice.
To make it worthwhile, I'd need to do what I usually do when designing a serious user interface, and examine the actual work flow of both professionals and hobbyists.  That way, I can make it efficient.  I'm pretty good at that, actually; I typically end up significantly speeding up users' workflows.
The problem in this is that many professionals, for some reason, completely drop interest when they find out it would use ngspice instead of ltspice, and I cannot understand why.  I know ltspice is a faster simulator, but nothing I've seen indicates it is more precise, numerically stable, or otherwise more reliable than ngspice.  Just faster.

There already exist a number of user interfaces to do this.  KiCad 7 and later are the most accessible (as in, both free, and available for most operating systems and architectures), but there are quite a few others.

Thus, in a very real sense, it is very, very much about the user interface, and not really about the simulator engine itself at all (except that because of Mike's choices, we cannot use LTspice's engine only; we either use the engine and its UI, or not at all).

From practical experience, the user interface affects your workflow efficiency more than you think or feel.  When you use a specific interface long enough, it does become muscle memory and thus both fast and with low cognitive load, but before that, you end up wasting a lot of time and effort before you get there.  (Plus, it is said that a human can get used to and comfortable with anything at all, possibly excepting an icicle up their butt, because that will melt before you get used to it.)

For example, there is no good technical reason why simulation results are not shown as the simulation progresses, why running a simulation should preclude other work on the schematic or symbols, or why you couldn't run several simulations (with the same or different schematics) in parallel.  (KiCad 7 + ngspice precludes all those; I'm not sure about LTspice on native Windows/MacOS.)
It all depends only on the UI, and exactly how the UI is connected to the simulation engine.

And my point is, we fundamentally could do better with what we already have, except users are not interested in helping to find out what that "better" would be.  It seems the more professional you are, the more intent you are in hoping for an Authority like Mike Engelhardt tells you what that is.

[mawyatt]

The history of Spice is interesting. Larry Nagel at Berkeley developed SPICE in 1973, and recall Berkeley licensed SPICE to all folks for $25. Many folks took this license and started all the various SPICE flavors back then, these were all text based "net-lists".

Microsim PSPICE was one of these folks and later developed a Schematic Capture interface to the core SPICE engine. Cadence appeared much later and developed their versions with much improved convergence and speed. Recall their ability to "spot" tiny circuit nuances, where traditional SPICEs would completely overlook such and the skip by these in TD simulations. Because of the superior SPICE performance linked with good IC layout tools Cadence became the popular design tool for most IC designers, even tho quite expensive.

Best,   

[Nominal Animal]

Yep, the original SPICE was open source.  ngspice itself originates from SPICE3f5 (written in C).

As I am a hobbyist on the electronics side, ngspice is the only SPICE I've really used, but I've also used QUCS and QUCS-S.  I don't currently have any licenses to run Windows or Mac OS (on hardware or virtually), and while Wine exists, it is far from perfect, so I don't want to form any opinions based on running LTspice, PSPICE, TINA-TI etc. on top of Wine.

The list of no-cost electronics circuit simulators is very interesting.

I was surprised to find that Sandia National Laboratories' xyce is also no-cost and open source, and even SPICE-compatible.  Surprisingly, very few posts here mention Xyce at all, and it is obviously (and publicly) developed for Sandia Labs' internal use (with the GPL'd version not including any national-proprietary bits), so I wonder if any professional members have used it for circuit simulation.  Perhaps it is my background showing, but I really like how its mathematical basis is explicitly documented.  Parallel processing requires OpenMPI making it better suited for distributing simulations (for example, in a HPC cluster) than utilizing multiple cores in the same desktop processor, though.

[mike449]

I don't currently have any licenses to run Windows or Mac OS (on hardware or virtually), and while Wine exists, it is far from perfect, so I don't want to form any opinions based on running LTspice, PSPICE, TINA-TI etc. on top of Wine.

From my experience, LTSpice runs faster under Wine than on native Windows. The difference in the installation time is especially dramatic. This is most likely because of the Windows antivirus snooping on all activity.

[Zero999]

I don't currently have any licenses to run Windows or Mac OS (on hardware or virtually), and while Wine exists, it is far from perfect, so I don't want to form any opinions based on running LTspice, PSPICE, TINA-TI etc. on top of Wine.

From my experience, LTSpice runs faster under Wine than on native Windows. The difference in the installation time is especially dramatic. This is most likely because of the Windows antivirus snooping on all activity.

I don't see why that should be the case. I find LTSpice running under WINE much slower for file operations, compared to Windows. It takes a long time to change from one directory, to another in the file selection box.

Regarding the GUI: most electronic design and simulation software have quirky, non-standard GUIs. I find LTSpice's reasonable, but I can see why some people struggle with it.

[mawyatt]

Recall in the 80s and 90s lots of shenanigans going on with the various flavors of SPICE.

HSPICE showing improved sim times compared to others, only to find that they had reduced the default convergence parameters in HSPICE to achieve quicker but less accurate convergence!!

Or DR SPICE showing improved sim times by partitioned the circuit into sections and each section assigned a separate SPICE engine and linking the sections together, only to find that the circuit they used for comparisons was DRAM which is highly repeatable sub-circuits which lends itself to this type of partitioning, most conventional circuits don't!!

Another SPICE flavor which partitioned the circuit and ran the different sections at different Time Rates and then attempted to "Stitch" the section together at longer Time Increments. This kinda worked on some circuits if the partitioning could be setup correctly, for example a high speed section would be simulated with smaller time steps than the lower speed sections like the Power Supply. However, this required careful assisting and tweaking from a knowledgable user for proper partitioning and often multiple trial/error attempts to make things work, and often was more effort/time than just running a traditional SPICE simulation and waiting for the result.

Lots of various versions of SPICE back then, which just compounded the situation and made things difficult for most users.

Reason we were so involved was we were in the middle of writing our own simulator specifically tailored for Silicon RFIC design based upon the core SPICE engine, but that's another story.

Best, 

[joeqsmith]

I've never used SPICE for anything outside of basic building block circuit design.   That part about Integrated Circuit Emphasis, is wasted on me.    My introduction was on a VAX.  Our output graphs were made using ASCII characters. 

I'm not a big user of LtSPICE as it's missing some features I tend to use.  When MicroCap was made available for free, I started to use it.   My history of SPICE:

[RoGeorge]

Agree the GUI is totally disconnected from the simulation engine and models.

Except in the case of LTspice, where they are inseparable, even though we have the exact information that the simulation engine needs.

The practical result of this is that LTspice only runs on Windows (7-10) and MacOS (10.15+) on x86 and x86-64, and has a single user interface.

Not sure what you mean by inseparable, LTspice can run a SPICE text-file netlists, no need for a GUI at all, plus there are a few libs already to call LTspice or to read the results from another program (first 2 search results):
https://groups.io/g/LTspice/topic/how_to_simulate_spice_netlist/58954862
https://electronics.stackexchange.com/questions/496593/using-python-to-simulate-an-ltspice-netlist
Also, I remember at least one funny use case, in which LTspice was called from another program, so to simulate analog electronic circuits, which analog circuits (their topology) were generated based on randomness + genetic algorithms.  And there was at least one unusual circuit resulted from that, which was verified in practice. 

About LTspice being for Windows/Mac only, for me LTspice always ran just fine on Linux.  It installs and runs out of the box, no WINE tuning required.

[Nominal Animal]

Correction to my claim above: it is possible to use only the simulation engine of LTspice.

I just found out that even LTspice can be used in batch mode without a GUI.  This means it is possible for example a Python 3 + Qt 5 graphical user interface to use ngspice or ltspice or xyce or other circuit simulators with a command-line interface for the actual simulation.  (While the LTspice compressed output format is not officially disclosed, it seems that it is already known and relatively stable, as a Python module already exists.  One can always use ASCII output format anyway.)

I think this changes a few things for me personally.  Time to setup a virtual machine with most recent Wine, LTspice, ngspice, et cetera, and do some experiments.

Not sure what you mean by inseparable

We posted at practically the same time.  I only now found out that LTspice batch mode does not invoke the interactive GUI.  It does need the related libraries et cetera, but it will not create any actual visible windows, which means it can (at least technically) be used as a simulation backend.

[iMo]

..
Also, I remember at least one funny use case, in which LTspice was called from another program, so to simulate analog electronic circuits, which analog circuits (their topology) were generated based on randomness + genetic algorithms.  And there was at least one unusual circuit resulted from that, which was verified in practice.  ..

So, you may now integrate the LTspice with the ChatGPT results, automate the KiCAD to draw the pcb out of the LTspice schematics, then automatically send the pcb files to China and just wait on the populated ready to run board.. 

[RoGeorge]

graphical user interface to use ngspice or ltspice or xyce or other circuit simulators

For the potential project of a new GUI (no matter the engine), I remember a nice feature from LabVIEW:  the picture of a drawing (.png ) was also containing the schematic, embedded in some picture descriptor tag, don't recall the details.  The effect was that one could drag&drop a schematic picture from any webpage, and run the "picture" locally into LabVIEW.  It was an impressive gimmick when I've first found out that was possible at all, to "run a picture". 

LTspice can plot "live" during simulation, though this is not of much use since most of the time the simulation completes almost instantly.  As for longer 1+ minutes simulation, live plot is not that great, because it slows down computation (long simulations implies millions of datapoints crammed into a small plot of a thousand or so pixels width.

Sure, tons of improvements can be added to LTspice (or to any other GUY), for example one feature that I almost implemented once in LTspice (unintended) was to add live "Slider", but then I've discovered QucsStudio already has sliders, and used that instead of my Python + matplotlib sliders cobbling.  The "live" sliders feature is absolutly great to have (particularly when learning), but is only works if the simulation is fast enough to finish in less than a second (the slider drag event starts a new simulation + plot update).

This is a 1 minute video with a slider (in QucsStudio, a slider is attached to the coupling factor, and another to a capacitor, then the effect of changing K or C can be seen "live" upon the two coupled oscillators, the resonance of the other circuit is affected/pushed by dragging the respective sliders): 


Might be common knowledge, but to me, seeing the line splitting (live) was one of those "aha!" moments, with deep implications  (way outside of the electronics area).  My point is, live interacting with the values in a schematic can be a very powerful feature, LTspice/ngspice/etc. can have this feature, too, such sliders are a GUI feature.