There seem to be three SE sites related to electronics:
- Chiphacker, a rather active SE 1.0 site which I think is about to be upgraded to SE 2.0
- Electronics Exchange, which I only just found out, linked from this question, it looks to be pretty dead
- Electronics and Robotics, a new SE 2.0 proposal currently on Area51 in the Commitment phase
To me, it looks like they all have the same scope. Shouldn't just one electronics site be enough?
EDIT: For reference, there's now a question on Chiphacker itself about this: http://chiphacker.com/questions/3876/what-about-electronics-and-robotics-in-area51