How do you design printed circuit board?
If you want to know a printed circuit board is designed here is the explanation in simple terms.
1. First you decide on the components which are in the design.
2. Need a software in which you can get symbols (both schematic symbols and physical symbols) of standard components and which also allows you to create your own symbols for new components which are not in the standard tool library.
3. In schematic capture tool, you will use symbols of components and also connect the pins of components with wire lines to complete the schematic drawing. Based on complexity and size of the design this can be few pages or hundreds of pages.
4. In the layout tool you will have to make a board outline (based on the shape/size of PCB you want to design) and define number of layers etc.
5. Schematics need to be exported to layout using the board outline you designed. Result will be that all the physical symbols will appear in the layout tool along with un-routed wire connections.
6. Now you can place components on the PCB based on floor plan (where you want to place what components) and start routing the connections. Decide thickness of routes or traces based on impedance and current these nets need to carry. Based on how many layers have been defined and needed as per design traces can run through multiple layers
7. When routing is complete, with help of tool you need to create PCB fabrication data for PCB fabricator.
These are top level steps involved in a PCB design. There are finer steps like back annotation (process to sync up layout and schematics) which also important. Many tools give options for auto placement, auto routing which can aid in the design. These used with proper constraints and care can help speed up the design process. Check for PCB tool vendor websites.
Go to www.circuitboards.com scroll down to the links area and click free cad software by cadsoft. My friend told me the other PCB designing software mentioned makes you pay for there software if you want it manufactured outside of there facility. Basically locking you into there price or no price. Cadsoft is free up to a certain layer count I believe.