i need to draw some wiring/connection diagrams. any free software? Thanks!

 

To say the truth, you cannot get That good circuit stimulating software free. You need to buy them. However you can try this Free Circuit stimulating software which I use. Click on "Click here to download the ZIP file (5.67 MB)"

http://my.ece.ucsb.edu/York/Bobsclass/2C/Simulation/circuit_maker.htm

 

ExpressPCB is a very good free software. I use it to make PCBs.

 

Pad2Pad is a Free PCB design software.
http://www.pad2pad.com/

 

I'd vote for ExpressPCB too. Pretty intuitive. Not a huge library, but very easy to make any new component that isn't there.

Ken

 

EpressPCB is a good starters choice. I still use it some.

Kicad is a great package that can also take you thru PCB designs. It has as steep a learning curve as any other full featured layout program.

LTspice is also free and a pretty good simulator, not just with LT parts. I'm just starting to use it and like it.

 

I agree with the others--ExpressPCB is a good place to start, but don't get hung up on it if you plan to do more extensive wiring and/or PCB design. For that I'd recommend Eagle, KiCad, or DIPtrace. All of them have free versions.

If it's a simulator you're looking for, try LTSpice, from Linear Technology, like ErnieM suggested. You can also get free trials of Multisim, which is actually my preferred simulating software (right behind Proteus ISIS). However, both ISIS and Multisim will require you to purchase the software if you want to keep using it after a certain amount of time.

Hope this helps!
Matt