Tips for Verifying PCB design

[bitman]

I'm an electronics hobbyist; while I've done quite a few circuits on breadboards and prototype boards, I plunged into a real PCB this month for the first time.  Of course I screwed up - while I had a prototype of the circuit working on a breadboard I made a mistake on the schematics and didn't see that until I put everything together on the PCB.

My question - what methods can I use to verify that the schematics/PCB actually does what I think it does?  KiCAD doesn't seem to have a simulator, but in this case it wouldn't have worked since I started in the "simulator" and just made a mistake putting it into a diagram that I used to design the PCB with. My circuit is very simple (<50 components) - I'm left with being a bit puzzled at how you test this stuff on a lot more complex boards. Do you keep producing prototypes, solder everything on and see if that works? Or do you have to develop the skills to discover the mistakes in the schematics?

I work with and spend a lot of my time with software development and advanced computer systems. I know how we test/verify software. Things are broken up into smaller pieces and each piece is put together, tested and then multiple of smaller pieces are tested together. There are a lot of different types of tests done - from functional, to error handling, performance etc.  What does this look like when designing something physical like a PCB?

[Ice-Tea]

- Checklists for common mistakes (example: http://pcbchecklist.com)
- Peer review

[JonPyro]

You can get a correct schematic and still find it doesn't work on a PCB, I have come unstuck with capacitive effects before now which didn't show on breadboard. Board routing can be just as critical to prevent cross talk and other such problems. I have also used a CPLD library footprint that was wrong and spent hours trying to debug the board before I found it.

Ultimately, designing pcbs is an art as well as a science!

I often design more into a board than I plan to use, like extra component holders for decoupling, or links to connect subsystems that make debugging a lot easier etc.

I spent many years home etching and that teaches you alot about making boards. Now China pops them out for a few dollars you can be too quick to order and make silly mistakes.

[james_s]

I usually send it to a friend and have him look at it, a second set of eyes works wonders.

If it's a simple circuit then build another prototype based off the schematic, better yet start with the schematic before you do anything else and then build your first prototype from that.