Fritzing is an open-source hardware initiative that makes electronics accessible as a creative material for anyone. We offer a software tool, a community website and services in the spirit ofProcessing and Arduino, fostering a creative ecosystem that allows users to document their prototypes, share them with others, teachelectronics in a classroom, and layout andmanufacture professional pcbs.

Another good alternative:

1. Eagle PCB – a PCB designer –

2. Filter Lab – Filter designer –

3. Filter Pro – Filter designer –

4. LtSpice – Design Simulation –