The Saturn PCB Toolkit is the best resource for PCB related calculations you can find. It incorporates many features that PCB designers and engineers are in regular need of like the current capacity of a PCB trace, via current, differential pairs and much more.
Neat, easy to use PCB designing tool.
It allows you to display data using no fields or relationships.
This program is a great tool for simulating electrical circuits.
Tool for seismic signal processing in graphical interface
User friendly Windows Util to easily convert between 902 units of measurement.