Freeware or low cost schematic software?

Hey, is there any decent freeware or low cost schematic software out there that's good?

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Yours In Liberty,  Melissa  - Colorado, U.S.A.
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Melissa
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Express PCB has a free schematic and PCB layout software. The PCB layout software generates a file you send them for making of boards; pricing is given in advance.

Reply to
Robert Baer

Linear Technology offers a free Schematic Capture and Spice Engine called Switcher CAD. There's a Yahoo group to help with any issues and the bug fixes come very fast.

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Orcad has a limited version of PSpice with Spit! a Schematic capture front end called "Capture".

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And Terry Pinnel has a page listing low cost or free CAD packages available.

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Robert

Reply to
Robert

Some of us are smart enough to use "Custom Installation" and choose the venerable old MicroSim style schematic capture ;-)

Although... I just remembered... this year you must download it separately.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Jim Thompson

Target3001 schematic package works for me....

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The following PCB fab company has a free version of Target3001 that you can download...

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specifically..
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The reason it's free is that the PCB layout side of the free version is linked to their PCB fabrication service - so if you want other companies to be able to fab your PCBs you need the paid version from the above.

Colin

Reply to
CWatters

there

I use gschem. It is part of the gEDA package. I have had no problems with it. It only runs on UNIX like operating systems such as GNU/Linux, BSB and MacOS X. I may also run using cygwin in MS Windows. It is good enough that it is worth insalling one of the Linux distros to use. It is free software (GPL).

You can download it at

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One thing to consider in schematic software is the possibility of making decent looking output. gschem will create postscript files which can be converted to PDF with ps2pdf. I have seen some ugly pixelated schematics from other packages.

Darrell Harmon

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Reply to
dlharmon

Thanks!

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Yours In Liberty,  Melissa  - Colorado, U.S.A.
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Reply to
Melissa

Is it free or shareware?

Is it a timed demo? I shudder to remember the prices Orcad used to charge, when I last worked in electronics ( early 90's ).

Thanks Robert!

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Yours In Liberty,  Melissa  - Colorado, U.S.A.
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Melissa

The TARGET3001 is a good CAD tool and does also offer a free discovery version. ...richard

Melissa wrote:

there

Reply to
richard

I guess when you get something for "free", you get what you pay for. I downloaded it because I wanted to try out this spice stuff, never have before. I was thinking of looking at a crystal diode detector circuit and seeing how it modeled it, but they don't have any germanium diodes in there. Darn.

Yes, I actually have some germanium diodes, after all these years, in my lab drawers somewhere, brand new. :)

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Yours In Liberty,  Melissa  - Colorado, U.S.A.
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Melissa

I have thrown out Protel schematic at work and now use TinyCAD - a freeware schematic editor which I reckon is heaps superior. TinyCAD exports a netlist which I suck into Protel to do the PCB.

TinyCAD is easy to learn, with Windows standard controls, so you don't have to remember how to drive it. The schematics look good when printed. It can do big jobs with many sheets, so it won't run out of grunt.

It loads and runs fast on Windows, so you can use it for a quick diagram. You can copy and post bits of schematic from it, which is great for documentation or email.

My only warning is : look at but don't use any of the supplied libraries. They are donated bits and pieces, sometimes gotesquely mismatched, and with pins off grid may not actually connect when you expect. Start your own library with pins nicely on grid and all will be well.

Roger

Reply to
Roger Lascelles

there

freeware

have

can

with

Forgot to give the TinyCAD link :

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Reply to
Roger Lascelles

I'd heard that wasn't available in the later (after 9?) demo versions. Perhaps it was just the separate download that made me think so. Glad to hear I was mistaken.

Robert

Reply to
Robert

Free. And the download page has other software that may be useful.

Restricted to 10 transistors per page (last time I heard) but you can make subcircuits for more. No time limitation.

You're welcome. Robert

Reply to
Robert

In article , Melissa wrote: [....]

Linear doesn't make germanium parts. Remember that LTSpice is a sales tool. Linear will put in the models that they see as being in their best interest to put in. They also make an effort to make their models represent what their parts really do.[1]

[1] The LT1246 model is/was not really right. When asked about it they said basically "oops".

The spice engine and schematic capture are very good and fairly good[2] respectively and you can add your own stuff it. It is not a closed system. I often use it to model TL072 circuits and it does not explode when I do so. Having it does bias me towards using a Linear part where two roughtly equal parts exist. As a result, you will see a lot of LT parts in a design I do today.

[2] Mike: I'm not refering to the problem with the ATI driver here. Even under Windows (or on a none ATI system), the scrolling and zooming in the schematic capture get it wrong. It is a slight bother. The center point moves semi randomly when you zoom and the scrolling won't let you scroll far enough off the edge of the existing circuit. The work around is to stick down a couple of texts.

The fact that it runs under Windows is becoming less important to me than the fact that it runs under "wine" on my Linux systems.

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Reply to
Ken Smith

LTSpice/SwitchCAD doesn't have a lot of parts apart from their own, but that's perfectly understandable given that it's free and that it's the whole point of releasing it in the first place.

It's compatible with any (almost) Spice model you will throw at it, and creating new parts is very easy. So just look for a Spice model for your diodes, read the online help, create your diode parts and start simulating - simple as that. I've created a few parts (INA163, OPA134, OPA137, TLC272, various JFET and MOSFET transistors, etc) and it works very well for me.

Reply to
Guillaume

and

Can you create a germanium diode with a .3V forward voltage drop?

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Yours In Liberty,  Melissa  - Colorado, U.S.A.
http://melissasliberty.blogspot.com/
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Reply to
Melissa

Why thank you sir. :)

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Yours In Liberty,  Melissa  - Colorado, U.S.A.
http://melissasliberty.blogspot.com/
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Reply to
Melissa

Yep.

Open the file 'standard.dio', which is located in the lib\cmp subdirectory of the installation directory, as a text file.

Then just add the following line (copy and paste) at the end of this file (on a single line):

..MODEL 1N34A D(IS=2.6u RS=6.5 N=1.6 CJO=0.0p EG=0.67 BV=25 IBV=0.003 type=Germanium)

Save it and restart LTSpice/SwCAD III.

Now when you pick a diode you should be able to select the 1N34A, which is a germanium diode that should fit your needs.

I haven't thoroughly tested this spice model but it seems to be working fairly well.

Reply to
Guillaume

I read in sci.electronics.design that Melissa wrote (in ) about 'Freeware or low cost schematic software?', on Tue, 22 Mar 2005:

Yes, but to understand how the model works, you first need to understand that diodes don't actually have a 'threshold voltage' of 0.3 V for germanium or 0.6 V for silicon. The relationship between current and voltage is exponential (plus the effect of some series resistance), so it looks the same whatever scale you look at it on. The 0.3 V and 0.6 V come from the fact that those voltages apply for smallish practical currents, e.g. 1 mA to 10 mA. The models, however, use the 'exponential voltage-controlled current source in series with a resistor' interpretation.

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John Woodgate

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