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 .

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.

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: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

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

[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....:)

Qucs !

[Ruie]

Qucs is very capable.

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.