The machine schematic sector is full of very expensive tools. We used to use Via Wiring Diagram (which was bought by AutoDesk & become AutoCAD Electrical, now about $5K), but felt it wasn't worth it to keep up with the various yearly fees. Then our licensing server died and we moved to Win7-64, so Via WD is now dead and I've spent too much time looking at solutions.
Unless your schematic is really simple, I don't recommend using straight 2D CAD (AutoCAD or its clones, etc).
I took a look at using Eagle PCB schematic editor and quickly decided it wasn't a good fit.
Of the expensive vendors, I was most impressed with IGE+XAO and Aucotec Engineering Base; both are ~$3K for the limited entry level package + annual maintenance. However, we're very likely to move to Radica Electra, which is ~$1K with free support (no annual maintenance) -- I haven't had time to do my "due diligience" first (download the trial version and make sure it works for us).
Other affordable / semi-affordable schematic products I found included Elwin (29 euro), CADprofi (400 euro & up + AutoCAD clone), PC Schematic (limited free version), and WS-CAD (looks like ~$1K and up, plus annual maintenance) . They weren't good matches for us, but they might work for you.
@Aeroengineer ...The fact that changes do not automatically propagate through the entire design. It is rather tedious and error prone when trying to update something. ...
It's still easier than one of the higher end programs that I've used where you have to produce a net list from the schematic then do a compare to generate a change file which you can finally apply to the PCB... At least DipTrace has an update from schematic feature that eliminates several error-prone steps from the process.
I know that both DipTrace and DesignSpark PCB allow for that. I am almost sure that all the others that I mentioned will also allow for that as well, I just do not yet have any experience with these packages. I will soon enough.
I have been using DipTrace, and I do like it for it being intuitive. There is one thing that I really do not like, and I consider a fatal flaw. The fact that changes do not automatically propagate through the entire design. It is rather tedious and error prone when trying to update something. That aside, I can say that it was a package that I was able to pick up and have a board designed in under a week of an hour or so after work.
Sam, I have heard that SprintPCB is a nice package, though it was missing a few features that I was looking for in my search. It is one that I will be watching. I have heard many say that they particularly like some of the features.
Bill, I did actually look at that one, but it did not come close to meeting the things that I had laid out for what I am looking for in my PCB tools. There are tens of other packages that are out there, and while I do not minimize their value, they just did not meet what I am personally looking for. Thank you though for mentioning why you like you find gEDA appealing.
I missed any reference to gEDA which must be the first open source schematic capture tool. It's still available with PCB layout tool at
along with KiCad, which was mentioned. It was originally designed to run under Linux, but versions are availalbe that run under other operating systems.
Someone asked for Spice compatibility, and gEDA goes one better with it's own improved version of Spice - ngspice - which offers native digital and mixed mode simulation.
I've not used any of these packages for any serious work - I've downloaded them from time to time whenever I up-grade to the next version of SuSE Linux, and created the occasional schematic, but that is as far as I've gone.