Circuit prototyping software?

[milkyspit]

Where can I get my hands on some decent electrical circuit prototyping software, preferably free? What I mean is software that would let me basically "draw" a schematic on the screen, then model current flow through that circuit so I could check V/I/R at various points, or see how component X functions when voltage V is applied, etc. Features beyond this are of course nice to have, but not absolutely essential. I'm only a poor little hobbyist and would like a tool to model simple circuits such as regulators before building them in reality, and without the tedium of hand-calculating V/I/R throughout.

 

[MrAl]

Hello there Scott,

There's a program called "SwitchCad" that will do
exactly what you want. It's available on the
Linear Tech site. Look under the download section.

Take care for now,
Al

 

[Ray_of_Light]

You may want to try Electronic WorkBench. It allows you to define parameters for components not in its library. Or, if you want to go seriously in electronic modeling, there is PSPICE.

Anthony

 

[MrAl]

Hi Profit,

Is that free too?
SwitchCad is a free download in it's full version.

Take care,
Al

 

[Entropy]

If you are willing to manually enter the circuit description in a textual format, there are a number of open-source SPICE variants. I think some may have free frontends.

MicroSim PSPICE is a commercial package, although it USED to have a free educational trial version that was quite functional.

I'll check out SwitchCAD.

 

[Doug Owen]

[ QUOTE ]
MrAl said:
Hello there Scott,

There's a program called "SwitchCad" that will do
exactly what you want. It's available on the
Linear Tech site. Look under the download section.

Take care for now,
Al




[/ QUOTE ]

Howdy Al,

Help, I can't find it. I assume 'Linear Tech' is Linear Technologies, the IC folks. I can't find any downloads at all like that (a few Spice bits and an evaluation program or three). The name SwitchCad bounces on Google......

Can you please point me in the right direction?

TIA

Doug Owen

 

[Entropy]

I just looked.

It's SwitcherCAD, not SwitchCAD. Check Linear's sitemap.

 

[MrAl]

Hello again,

Yes, it's name is SwitcherCad and a url that will
get you there is:

http://www.linear.com/software/

I've personally tried this software, and although
it takes a bit of getting used to, it works :-)

I've added new models and even new circuits, so
it pretty much does everything if you are willing
to take a little time with it.

Thanks to Entropy for the name correction.
BTW, Bridgewater, i'm one town over, in B.Brook
:-)
We have several other NJ posters in this forum too.

Take care for now,
Al

 

[milkyspit]

Thanks MrAl and others! I downloaded the software too, and since it comes with models for pretty much all Linear Tech's product line, it ought to be quite useful in designing flashlight regulation circuits. /ubbthreads/images/graemlins/thumbsup.gif

Quick question regarding SwitcherCad: does it simply model whatever circuit I input, or does it also have a "solver" mode where I could find the value for a particular component -- a resistor, for example -- to achieve a particular specification on the output? It would be great if I could tell it, for example, that I wanted the output to be driven at 60mA (or whatever) and have the software plug-in the correct value for a relevent resistor. Is this somehow possible, or am I dreaming? (Maybe I'm just being lazy. /ubbthreads/images/graemlins/smile.gif )

Regarding NJ: I'm in Bridgewater often! I live in the tiny town of Califon, somewhat close to Clinton, and occassionally like to browse through those big Circuit City, Wiz, and P.C. Richards stores just off the Somerville Circle. /ubbthreads/images/graemlins/smile.gif I also recently bought a vintage transistor radio from a guy in North Plainfield (he's not a member of this list, unfortunately), so I'm familiar with you folks' neighborhoods. /ubbthreads/images/graemlins/grin.gif

 

[MrAl]

Hello again,

Im not sure if it has that solver mode or not. I know
some commercial software does.
If it doesnt, it's not really that hard to change the
value a few times and watch the output change. You
can then get a good idea what value to use.

If the software lets you spec a resistor with a voltage
source, you can also set up your own feedback circuit
that forces the resistor value to a level that forces
the output to a given current level. Reading the
final voltage level then tells you what the resistor
value should be. This is kind of interesting to do
in itself :-) but i would recommend just changing the
resistor a few times until you get used to the software.

Oh and, the Somerville circle, i've been there many times
and even to those three stores you talk about many times
also :-)

Many years ago i've done some fishing in Califon's
streams too.

Take care for now,
Al

 

[Entropy]

I used to pass through Clinton all the time driving back and forth to school (Ithaca, NY), but Route 31 traffic has gotten so bad that it no longer beats taking 78 out to (33???) in PA instead of taking 31 to 46 to 80.

I do much shopping at Circuit City and Best Buy. /ubbthreads/images/graemlins/smile.gif Not much of a Wiz or PC Richard fan though. Also nice having two Home Depots, a Wally World, and Target within 10-15 minutes for hunting down new hosts for mods. /ubbthreads/images/graemlins/smile.gif