Cheap, Cross-Platform Electronic Circuit Simulation Software?

dv82 writes "I teach circuits and electronics at the undergraduate level, and have been using the free student demo version of OrCad for schematic capture and simulation because (a) it comes with the textbook and (b) it's powerful enough for the job. Unfortunately OrCad runs only under Windows, and students increasingly are switching to Mac (and some Linux netbooks). Wine and its variants will not run OrCad, and I don't wish to require students to purchase Windows and run with a VM. The only production-quality cross-platform CAD tool I have found so far is McCad, but its demo version is so limited in total allowed nets that it can't even run a basic opamp circuit with a realistic 741 opamp model. gEDA is friendly to everything BUT Windows, and is nowhere near as refined as OrCad. I would like students to be able to run the software on their laptops without a network connection, which eliminates more options. Any suggestions?"

Comments

Is a live DVD OK?

[Anonymous Coward]

If booting off a live DVD is OK then you may want to look at https://fedoraproject.org/wiki/ElectronicLab_Spin .

Re:Is a live DVD OK?

[Anonymous Coward]

You sir, are an idiot, or at least the company you work for is.

The last thing you should care about is what brand of software someone
used to learn engineering. This is tantamount to a building contractor
only hiring framers who use "Stanley model 13 hammers".

You should be trying to determine if a candidate actually knows how to
design and solve problems; not worry about what tools they used.

Of course I realize this is how industry operates. The depths of human
stupidity never cease to amaze and amuse, and sadden too, sigh.

Re:Is a live DVD OK?

[Hurricane78]

Then the question is, why you prefer OrCad? Vendor lock-in? Monkey see, monkey do? No clue? (Hiring manager != electronics engineer)

I think in those cases one might not want to work for *you*. ^^

CAD

[Klivian]

For simulation, you can get Spice versions for all platforms.

For the CAD part, there is the EAGLE Light Edition from CadSoft http://www.cadsoftusa.com/freeware.htm It runs on Linux, Windows and Mac.

Re:CAD

[Grishnakh]

I use KiCAD and it works quite well for designing PCBs, though it has some rough edges.

However, the discussion is about circuit simulation in college, which has nothing to do with PCB design. KiCAD doesn't currently integrate with Spice unfortunately, though that would be really nice. I don't actually know of any open-source stuff that does Spice well. The SPICE engines themselves are open-source (such as ng-spice), but they have no front-end at all, so you have to do everything at the command line, which is really rather clunky when you want to, say, look at graphs of simulation results.

When I want to simulate a simple circuit (not often), I start up a Windows computer and run an old version of Pspice (9.something) which is freely downloadable. The state of circuit simulation on Linux is very, very bad right now.

Re:Netbooks?

[Omniscient Lurker]

Legally you'd still have to buy windows to run it in a VM, a professor/teacher can't advocate piracy (well they could but the carious higher ups probably won't like it).

Partner with IT dept and get it hosted via RDP

[attemptedgoalie]

We had finance apps that students had to use in their coursework. Trying to get them to work on a Win/Linux/Mac system would have been painful and time consuming.

So we created a terminal server environment that let anybody RDP in to use the course apps. That way nobody had to pay for a real version, we paid for the terminal license.

That might work well for you rather than finding an app to support in 3 environments.

Good luck!

Re:Partner with IT dept and get it hosted via RDP

[kelnos]

Maybe, but the article summary specifically says the guy is looking for a solution that doesn't require a network connection.

JMCAD

[TrashGod]

You might look at JMCAD. I haven't built it since v0.08.087, but v1.4 is current.

Might not be what you need...

[Anonymous Coward]

This might not be anywhere near what you need, but this application definitely helped out my friend in his intro to electronics class

Falstad Circuit Simulator Applet

Really good on rudimentary stuff, done in Java for cross platform goodness.

Re:simple solution

[notreez]

The law is never plain and simple.

Eagle is no simulator

[Anonymous Coward]

Electronics CAD != Circuit Simulation.

Re:Netbooks?

[JesseL]

Whether running Linux or Windows - aren't you going to run into some serious horsepower issues if you try to accommodate students who own netbooks?

I don't see why. Most student level electronics simulation just shouldn't be all that CPU intensive. When I was an EE student 10 years ago, people did just fine with 150MHz machines running SPICE.

LTSpice and SolveElec

[Vario]

LTSpice is free as in beer and works nicely even with more complicated problems. There is only a windows version available, but Linux support with wine should not be a problem. http://www.linear.com/designtools/software/

For simple circuits SolveElec runs on windows and mac, has a very nice user interface and is a good tool for teaching. http://www.physicsbox.com/indexsolveelec2en.html

Re:LTSpice and SolveElec

[Anonymous Coward]

LTSpice[...]Linux support with wine should not be a problem

Actually, since way back when, Mike Engelhardt has taken pains to assure the WINE-compatibility of LTspice. (Notice that the capitalization in the name of that app only applies to Linear Technology's name.)
In an odd irony, in its current incarnation, support for Win9x was dropped in that "native" Windoze app.

...and if the submitter of the question really wants his kids to produce their own PWBs, KiCAD is the universal app (open source).
Cadsoft's EAGLE *used* to be an acceptable cross-platform tool--but not since they got into the DRM business. The EAGLE Virus

gewg_

Re:LTSpice and SolveElec

[dv82]

Thanks Vario ! I tried LTSpice on all three platforms (using stock WINE on Ubuntu and Crossover on Mac) and it works beautifully. In fact, it is easier to get up and running than OrCad in some ways, it has no net limits, and even does things OrCad can't (like print a schematic directly). The plotting tool accepts mathematical functions of time, node voltages, etc, so ideal and real results can be plotted simultaneously, just like OrCad. I will hand this over to a student for further testing, but from what I have seen, your suggestion has solved my problem.

Paul Falstad's applet

[Dust Puppy]

There is a nice applet at http://www.falstad.com/circuit/ - it might not be sufficiently sophisticated but it does at least handle op-amps.

Not a fan of (P/NG/LT/Berkeley)SPICE

[TerranFury]

I've had to use a handful of circuit simulators, and I've always found SPICE brittle. Perfectly reasonable circuits just refuse to simulate, even when good initial conditions are set. Now it's possible I've been doing something wrong. But on the whole I find SPICE deeply frustrating.

The most robust simulator I've used so far has been a demo version of SiMetrix. HSPICE also does a bang-up job... when it doesn't segfault. Unfortunately, HSPICE is very un-free (and buggy-as-hell), and although SiMetrix does have a demo, it's artificially limited in the size of circuits it can simulate.

Thoughts?

Re:Not a fan of (P/NG/LT/Berkeley)SPICE

[Andrew Sterian]

It's quite likely you've been doing something wrong :-) I was at the same place, getting frustrated because perfectly reasonable circuits refuse to simulate. 99.9% of the time it was my fault, and it was a great learning opportunity. "Reasonable circuits" are not necessarily practical circuits. For example, you can put in an ideal switch into SPICE and cause brittleness, because practical circuit voltages and currents don't change instantaneously like ideal switches do. "But wait!", you say, "Inductor voltages can change instantaneously! That's what it says in my textbook!". No, they can't :-) There's a reason SPICE lets you specify an inductor's parasitic parallel capacitance.

Also, another source of brittleness/bugginess is poor third-party circuit models. I've downloaded some MOSFET models that just plain stunk.

BTW, LTSpice is my favorite simulator, hands down.

Re:Not a fan of (P/NG/LT/Berkeley)SPICE

[sdot1103]

I just spent the past summer doing research at the 22nm level (designing L1/L2 caches with DVFS and other low-power techniques) and I can't agree more on SPICE/HSPICE's inability to converge.

I shrunk my designs down to the criitical paths (~12k transistors), and even providing the proper nodesets/initial conditions HSPICE was unable to converge or segfaulted quikcly. Fortunately, my university has a deal with Cadence through their University Alliance program -- Spectre may not be quite as accurate at HSPICE for analog circuits, but both it and Ultrasim (a FASTSPICE simulator for large designs) can handle much larger digital designs without complaint.

To the original submitter: Is there a good reason behind the no network connection requirement? If the university has a proper setup, students should be fine either on or off campus -- then it may be worth checking if your university has any deals with either Cadence, Synopsys, or Magma -- their tools are primarily Unix-based (Solaris, AIX, and Linux support), so it's just a matter of having the students SSH in with X forwarding or use VNC. This would even allows users with underpowered machines to simulate large designs quickly since everything is done remotely. I primarily run Windows on my local box, but either VMs with Linux or using Putty with Xming work properly for all these tools.

Re:Not a fan of (P/NG/LT/Berkeley)SPICE

[bitrex]

Real men don't need no stinkin' simulators! We just write down the equivalent circuit models, use Kirchoff's current law and apply Cramer's rule! Nothing's more exciting than spending a leisurely weekend computing the determinant of a 258 element matrix in the s-plane by hand. Frequency response sometimes takes a bit longer....:)

LTspice & TINA-spice

[The Lerneaen Hydra]

I've actually been in the same situation myself, two free (as in beer) SPICE derivatives I've found to work well are LTspice and TINA-spice (from linear and Texas Instruments respectively). They are windows binaries but function very well in WINE (in fact the developer(s) for LTspice have designed it to function as well as possible with WINE).

I've mostly used LTspice and it works very well and has a low learning threshold. Of course you can insert spice directives in the schematic to do more advanced functions like basic parameter sweeps as well as monte-carlo simulations and so on and so forth. Check out LTspice's yahoo group for a bunch of documentation.

As far as other recommendations for eagle go I doubt that's what you're looking for as eagle is solely for schematic capture and pcb design, there are no simulation capabilities in it.

Re:spice

[mkiwi]

I'm not sure why this is modded informative.

SPICE is the software that does the simulation- it is not a front-end anywhere near as good as OrCad. That's like telling someone who wants to write a formal letter to use vi (or emacs). In fact, OrCad does its simulation through SPICE.

IIEE who uses a Mac, and I have looked into this. I have not found anything usable across all platforms, which is a real pain in the butt. As the OP already knows, PSPICE is owned by Cadence so the copyrights and patents for the software are locked up in that. As a result, there really aren't any viable open source alternatives.

The only thing I could think of would be to do something with LabView but that opens up a whole other can of worms in terms of teaching students how to work.

My suggestion is to get your ECpE department to subsidize VMWare or Parallels for students so that they can run PSPICE in OrCad. The world is just kinda crappy that way.

I don't know...

[thatskinnyguy]

I don't know if it's been mentioned already or not, but Multisim from National Instruments is a very good software. It's been used by the professors at the school where I work for as long as I can remember.

Re:School Computer Labs

[Andrew Sterian]

It's the changing college demographic. First, more non-traditional students that want to be able to work at home, at "work", on their own time, etc.

Second, more demanding traditional students that expect colleges to come with more amenities like better dorm rooms than what used to be the norm, private bathrooms, etc. The ability to work in the dorm room or "plug in" wirelessly anywhere on campus and do their homework is becoming an expectation.

We have computer-aided teaching studios now with no computers in them. Doesn't make sense when every student has a laptop. Soon we will not need any computer labs.

Since when does literacy count for anything?

[attemptedgoalie]

I *totally* missed that.

I'll go sit in the corner.

Qucs !

[Ruie]

Qucs is very capable.

Linux?

[GWBasic]

What about Linux circuit simulation software? At least that can be run in a VM for free.

Re:Linux?

[bemasher]

I've used Oregano on Ubuntu with not very many problems. My original reason for trying it out was that the academic demo for OrCAD wouldn't simulate circuits large enough for my projects at school. I've found that it duplicates most of the features we used in courses on OrCAD. Oregano

Re:Linux?

[yope]

Please mod this one up! Oregano is indeed an excelent frontend (although with some rough edges and a few bugs) that whould run on Linux, MacOSX and probably also Windows, since it's built on GTK+.
It is quite easy and intuitive to use, works much better than gEDA, but needs some getting used to working around it's glitches, specially to discover a few tricks about how to work easily with any external spice subcircuit.
Simulation can be done through berkeley-SPICE, ngspice or GnuCAP.
It's a shame this is the only post so far mentioning it.

Re:spice

[jank1887]

There are a number of SPICE frontends. Right now I'm using the free LTSpice from Linear Technology. It's a professional quality code that the company releases for free since their main product line is actualy electronic components. The software comes with a full library of LT components of course. BUT, it's windows only. There's a Yahoo user group that may be able to answer questions about how well it runs under VMWare or Parallels, It supposedly runs well under Wine. (Winehq.org says "Works well with wine"). So that could take care of Linux and Windows users, but no idea with Mac. I know Mac users are whiny enough, but don't they have a Wine equivalent yet?

Re:spice

[willy_me]

VMWare or Parallels

Or you could try VirtualBox. I have tried all three and actually prefer VirtualBox even though it is free. On that note, many post-secondary schools have access to free Microsoft software. I know I can download just about anything for free via an MSDN portal on my university webpage - you just have to be registered in computer science.

In order to keep things easy for the students (they should be learning concepts and not software) just pick the best software for the job. Should it require Windows, so be it. Those who run other operating systems can work around it. And this is from a guy who hates Windows...

Re:simple solution

[KillerBob]

He's not exactly wrong, he's just deliberately misinterpreting the law to further his own agenda.

In this case, he's deliberately ignoring the part that says that such circumvention is legitimate for classroom purposes iff it's no longer readily available to acquire through legitimate channels, or only a small exerpt is actually required. In other words, you can photocopy a page from a textbook to use as a handout as an alternative to students forking over $150 for just that one page, or you can provide photocopies of books that are no longer in print, but you cannot hand out copies of software that people are still selling.

For pro software, the OS is secondary

[fermion]

I deal with the issue as well. Here is my opinion, take it or leave it. For certain pro software, you buy the machine that runs the software, no the other way round. So, in many cases, the Mac is not an option without a VM. I use my mac to run these tools, but I use a VM. For cad work, there is simply no substitute for Solidworks or Autodesk. For circuit and control work, it is National Instruments. There is a push to get these ported to the Mac, but so far to no avail. Autodesk does not run so well under the VM, so I often run it on a dedicated machine or boot into Windows.

I would say that it these students are in an engineering or science program, they must know how to use these tools, just like someone in a science/math program must know how to use Mathematica. That said, if the course in question is just a survey course, the specific tools may be less important than the exposure. For this there may be alternatives. For instance, an only breadboard simulator is available. Google circuit simulators and there may be more available. I am not sure what is available for CAD.

Here is another issue. If the class teaches the design techniques and not the application, the maybe students can use whatever they want. What distresses me is that we are no longer teaching the high level concepts, but the mouse based menu selection. Instead of teaching the concept of cut and paste, we are teaching the menu commands. The problem is when the menu changes, the students are SOL. For career training, this is fine, but I think we should be teaching at a higher level for college. For instance, in my college, we were just told to write a program to solve the problem or create a simulation. How we did it using the available tools were up to us.

Re:Use LTSpice

[Animats]

LTSpice is quite good if you want to design power supplies with Linear Technology components. The component library has just about everything Linear makes, and not much else. So you need some additional libraries for other purposes. You'll probably have to put together a model library for your students, from various downloaded models.

I've had fun with LTSpice. As an exercise, I've been designing hardware to run a Model 15 Teletype (1930s technology) from a USB port. The usual power supply for the 60mA current loop required is a 120VDC supply through a 2K 10W resistor, to get enough punch to energize the 4H 55 ohm selector magnet of the Teletype fast enough. Most of the energy is wasted heating up the big resistor. But I've designed something that up-converts 4.5VDC to 120VDC using an IC intended for photoflash applications, charges up a capacitor when the input is low, and when the input transitions to high (MARK), dumps the energy into the magnet. The 120VDC is only needed for the first 1ms or so of each bit time, to push current through the big inductance. A 3.3V linear regulator then provides the sustain current to keep the magnet pulled in after the cap dumps. The whole thing needs 250mA at 4.5V, which can be taken from a USB port. Separately, a small CPU is needed to do the serial port stuff for the signal.

Re:Why are you even using demo versions anyway?

[zippthorne]

No, if OrCAD is what he needs, he should pay for it. Or rather, the department should pay for it to be put on all or some department- or university-owned machines that the students have access to. The students have no real need to be able to do the work in the comfort of their own dorm rooms, although there is a convenience factor there which suggests using a package which also has an affordable student version.

But the reason students pay those high tuition rates is precisely so that the university will be able to afford the professional versions of tools (including software tools) that they will be using in their careers.

That said, the people who make OrCad would be pretty stupid to charge full price to a teaching institution. Not so much because of any ethical reasons (a university can probably afford full price. Their margins are high, and they bill on both sides of the equation: professors who also do research get soaked.), but because it is an excellent opportunity for indoctrination.

Been there...

[satan666]

Timothy,

You might find a version of your question pop up on most EE Boards at one time or another. Most people (including myself) had this sort of experience:
I started simulation with OrCAD/PSPICE/layout/ but I moved to Linux because I hated windows.
This is how it went down:

1. I refuse to use non-GPL software on my beautiful Linux box. I'll try the GPL/free stuff.
2. Damn hard road I've taken. I am writing SPICE code when I should be simulating and laying out my boards.
3. Ok, ok... GPL is out. That stuff needs a lot of work to become pro. Let me try the cheaper SPICE/Layout products.
        Tried, all the cheaper stuff, http://www.islandlogix.com/ (is probably the best).
4. Ok, BIG snag need 8-10 layers with diff pairs and 30-40 multipin devices. I need a serious autorouter.
5. Eagle, Electronics workbench, all are worthless. Only Mentor and Cadence can handle this.
6. Hello OrCAD, PCB Editor and PSPICE. How have you been my old friends? Nice to be back.
7. Hello Windows. You still suck.

What I am trying to say here is: any serious EE should know Mentor/Cadence. Hate me for saying this and mod me to hell.
It is what the industry is using and your hiring manager will not give a shit about your GPL/Linux ideas. He's got a deadline and a set
of tools that work and he wants you to come in and start working.

Before I close, I would like to send out a plea to Mentor and Cadence: Please, please, PLEASE consider porting to OSX and Linux.
If you are the first one you will OWN the market.

And that's my $0.02 worth

Atanua?

[ErnstKompressor]

http://sol.gfxile.net/atanua/

Not sure if it is what you are looking for. Hope it helps.

Multisim

[DCBoland]

I've used the Multisim/Electronics Workbench package under WINE before with no problems. I've seen it used in labs for teaching students, it should do the job just fine.