Best simulation software (for me)?

[Martin B. Kantola]

Turning to the experts, since I wish to invest in a new software that fits my needs. By searching this forum I found these candidates:

SIMetrix
CircuitMaker
Electronic Workbench
Micro-Cap

I'll probably never use anything really fancy, but what I would need the most is:

- fast and easy to use
- pretty reliable, bug free analog or mixed (mostly audio) circuitry simulation
- good library of models
- basic analysis (noise, FFT etc.)

Any good advice is appreciated!

Thanks,

Martin

 

[analag]

I was once told simulators are toys, so I've been using "pencil an paper".
Very slow and tedious.

analag

 

[Kev]

:roll:
yeah right ... toys

that list is pretty much at the bottom of the market and things like CM are not really sold and supported anymore.
I continue to use CM as the PCB side of things is compatable with the old DOS Protel.

you could also look at the NZ package of Rimu PCB
Tim Hudson I think ... a single person outfit with one to one support.
you may be able to get himn to write specific enhancments
no simulator here yet but I had to mention it just because of the ... "Windows MDI interface".
and it will export a useable netlist to import into a dedicated simulator


Simulators are useful but won't tell you how it will sound
currently most TUBE models are very simple and are wrong or at best incomplete

for digital and control there are excellent
for opamps there are fair and will tell you if you have made a outright mistake but won't tell you about noise floor or even ground loops ... you can spot them but the simulation won't tell you it's there

and the same goes for RF circuits

BUT
simulators are very useful and are so is 3D modelling

I use them as an aid to speaker design and crossover design.

How much you spend will depend on your expectations and reliance you out into the software. Fully spec'd Protel and Camtastic is very very expensive.

I know I'm not much help here.
but I had to say something after analog's over simplified and narrow response.
If you want a simple layout schematic and simulator then any of the Freebies could satisfy you
BUT
if you want a detailed and extensive software with the ability to wrinte your own models and enhance existing models then the sky is the limit and it is very likely you will want multiple packages and use the ones that give the best results for the given task

example
I use one package for simple single vented boxes BUT I use another for modelling Double Vented Bandpass ... because the first one gets it wrong.
I'm won't name them.

My Dad has been writting some models for the obvious tubes and so the open source models and simulators are useful.

Does anyone curently use this ?
http://ngspice.sourceforge.net/


final point
even a freeby in it's simplest form could tell you that a layout will at least function and the 3D render may give you a hint to what box or enclosure might suite you

if that's just a toy
then I like playing with toys ... and will continue to do so ... until I grow up

 

[Ptownkid]

Yeah yeah analag, we all know you're too cool for school.

However, I seem to recall seeing a whack of schematics drawn electronically by you on this board...

 

[ruffrecords]

onre of the most popular today is switcherCAD. Completely free and well supported. You can download it from http://www.linear.com/company/software.jsp

Ian

 

[Mbira]

I think Analag must be kidding, as he's one of the main users of simulations around here.

 

[Ptownkid]

[quote author="Mbira"]I think Analag must be kidding, as he's one of the main users of simulations around here.[/quote]

I hope so

 

[analag]

[quote author="Mbira"]I think Analag must be kidding, as he's one of the main users of simulations around here.[/quote]

Ah Kev missed the point, but you got it.
I use it to rough sketch my ideas, but I know fully well how optimistic it's predictions can be.
http://www.linear.com/designtools/softwareRegistration.jsp
I use LTSpice, nice and free.

analag

 

[Kev]

nah
Kev didn't miss the point

once again Kev plays devil's advocate for someone and you have missed that point.

Martin joined a year and a half ago and has had 12 posts and may not hang here often enough to get your humour.

I got an email from someone (not Martin) that speaks a different first language and has a different put together in humour.

you find it funny
some don't

My father used a mathematical model to predict the fluctuations in ground potential of the Ikara Missile casing
... as it is a little hard to measure while it was in flight.
what's Kev's point here ?
there is a specific point but I'll keep it to myself and my close mates ... (well I'm enjoying it and yes it could be annoying to many)

Simulators are just another tool.
...
and so are pencils

use them when you need to
:green:

so,
you use a pencil and then use the , nice and free LTSpice.
:roll:
... could have just said that in the first place..

 

[bcarso]

I still use circuitmaker for sims, but if you don't already know what you are doing it can be quite misleading. It is quick since the schematic directly drives simulations without need for transcribing netlists. I had been sim-averse for years and that was one of the reasons. But I can assure you that I generated many designs with pencil, paper, and an HP15C.

The layout people I worked with also pressured me towards schematic capture, and I have to admit, though I miss my yellow paper and Mont Blanc schematics, it is neater and easier to maintain using the program.

Circuitmaker is woefully short on magnetics models, and thus almost useless for switching supply design. And as Kev points out, it's not supported anymore. A programmer friend speculated that it had been someone's senior project and he or she decided to sell it. Then it became too popular and they had to hire people to upgrade and maintain it, and whoever was doing this got tired of having people yell at them about all the bugs (some amazingly stupid plotting routine ones among others---seems like those are the Achilles' heels of many a program).

A former client wanted to standardize on Orcad for everybody, since they had spent tons of money on it and the guy behind was a little empire builder. But for better or worse (certainly for poorer) they told me to leave before I was forced to learn the extremely intricate system. So I can't say whether its presumptive power is worth the staggering cost.

Ultimately, simulators are very valuable tools but too-early use provokes mental laziness and sloth, imo. I've seen people run to them to "simulate" a simple voltage divider.

 

[ruffrecords]

[quote author="Kev"]Does anyone curently use this ?
http://ngspice.sourceforge.net/[/quote]
I mostly run Linux and yes I have tried it, along with nutmeg which produces its graphical output. Despite being a Linux advocate I prefer switcherCAD, which runs fine under wine, for its ease of use and integration.

Ian

 

[analag]

[quote author="Kev"] you use a pencil and then use the , nice and free LTSpice.
:roll:
... could have just said that in the first place..[/quote]

But then, we would not have had this excellent interaction

Now....how can we get Brad to try LTSpice, it's free man. Every month I click on "sync release" and the program updates itself. Use it to suppliment CircuitBreaker.

analag

 

[bcarso]

[quote author="analag"][quote author="Kev"] you use a pencil and then use the , nice and free LTSpice.
:roll:
... could have just said that in the first place..[/quote]

But then, we would not have had this excellent interaction

Now....how can we get Brad to try LTSpice, it's free man. Every month I click on "sync release" and the program updates itself. Use it to suppliment CircuitBreaker.

analag[/quote]

I'll be getting to that soon, thanks for the nudge Rowan.

I often think of free things as worth about what you pay for them, but in the realm of computers and the internet this old gag seems to be losing its validity.

My sync problems right now are between my DSL modem and ATT, whose helpful bots and even flesh-and-blood representatives are finally making some real progress. Maybe.

 

[Svart]

I've seen people run to them to "simulate" a simple voltage divider.

Funny you should mention that, I have a little story for you about this.

I got quizzed at an interview recently, well a couple of months ago, the director of engineering decided to put down my resume and hand me a pencil and paper. He dictated a few circuits to be drawn and then asked me specific questions about the circuits. First off I see that he is testing my electronics vocabulary and also my symbol knowledge as well as listening skills and so forth.

One of the parts of the circuit was a 10k series resistor with a 10k shunt to ground, 5v feeding the circuit before the 10k series resistor. he asked me what the voltage was at the node between the two resistors was, without any other loads of course, and then asked me if I needed a calculator.

I immediately said, "nope, that is a voltage divider and the voltage is 2.5v."

He smiled and said something that made me feel good but also not good at the same time, "you don't have as much experience as a lot of the other applicants but you would be amazed at how many of them stated that they didn't know the answer to that since they would usually simulate the circuit and didn't even try to solve it."

I felt good about being correct but it really struck me how many folks are dependant on simulation and almost *need* it to do the smallest job.

I was allowed to sit in on an interview for a senior RF engineer, well it was a business breakfast and I was invited. The interviewee had 20 years of experience and talked almost entirely of simulations and his experience with a certain program. The interviewer asked him bluntly what his expectations were and how he thought he could get up to speed the quickest. His reply was that they would need to buy this program that he was used to (for some 10's of thousands). Last I heard the interviewee was not being pursued further.

Don't take me wrong though, simulations can speed up the design process by leaps and bounds but it can't account for human errors from the programmers or from the end user.

We have a thread about different types of regulators and their associated attributes. I've simulated a lot of those different designs and came to a point where I decided that sometimes good enough is actually enough, thus the reasoning behind one of my posts in that thread.

:thumb:

BTW, I use circuitmaker/traxmaker myself. I also use ltspice/switchercad some too. One circuit that I simulated from Analag, a HV MOS regulator for B+ simulated OK in LTspice but oscillated wildly in Circuitmaker no matter what I did to get a leash on the output. I never did build the circuit so I don't know which one was lying or why.. yet.

 

[analag]

[quote author="Svart"] One circuit that I simulated from Analag, a HV MOS regulator for B+ simulated OK in LTspice but oscillated wildly in Circuitmaker no matter what I did to get a leash on the output. I never did build the circuit so I don't know which one was lying or why.. yet.[/quote]

Ah, but I have so guess which program is lying. In fact I have about ten of them in daily use and nary a problem. It's a simple circuit, why don't you take a few seconds and lash it together. Run the tests, man.

analag

 

[Martin B. Kantola]

[quote author="Kev"]Martin joined a year and a half ago and has had 12 posts and may not hang here often enough to get your humour.[/quote]

Hanging in this place is a delicate balance between getting your sense of humor twisted and learning useful stuff in audio electronics. So I try to stay away a lot.

Anyway, thanks a lot for all your help so far! Checking out the software you already mentioned, but the popular CircuitMaker is not available anymore, or?

BTW, here are some lists I found:

http://www.web-ee.com/Downloads/Simulator/simulation.htm
http://www.epanorama.net/links/software.html#analysis


Martin