The CPU( central processing unit ) is the brain/heart of the computer, notebook, netbook, iPad, iPhone, iPod, Android mobiles and BlackBerry, it’s actually an electronic circuit, TinyCAD is a free and open source circuit diagram design software for Windows, you can use it as an alternative to VeeCAD, AutoCAD, ExpressPCB, Cadence OrCAD and Easy PCB.

Features
- Zoom in or out with mouse wheel.
- Several hundreds of predefined components( symbols ) available, including Quand NAND gates, Input NOR, Bridge Rectifier, Small Green Radial LED, NPN Transistor, LED( Light Emitting Diode ), etc. It also supports custom symbol libraries.
- Very detailed document available.
- Create PCB( printed circuit board ) net list: export the design’s netlist for import into a PCB drawing application, supported output file formats: TinyCAD, PADS-PCB, Eagle SCR, Protel, gEDA PCB, XML, etc.
- Check design rules: duplicated reference, unassigned reference designators, non-case distinct net names, etc.
- Generate symbol references.
- Export part list to plain text file or CSV file.
- Create spice net list.
- Export as png or emf picture files.
- Allows to print and print preview.
- Automatically backup every 10 minutes.
- Auto snap wires, auto drag wires, auto place junctions.
- Show the grid, snap to grid,
- Customize colors for wire, power, junction, bus, pin, no connect.
TinyCAD supports all 32-bit Windows operating systems including but not limited to Windows 7, Windows XP.
More Reading
TinyCAD is a 4.4MB download available from SourceForge.net.

awsome program
Thanks!!!