yEd graph editor is a very essential tools to draw your own block diagrams and graphs. As a computer science personnel, I personally use different block diagram and flow chart to explain different algorithm. yEd provides easy customized blocks to draw your block diagrams. You can also add different logos such as user, computer, workstations, etc. easily in yEd. It is a very useful software for drawing and building scientific figures. Another best thing of this product is that it is completely open source and free.

Sencillo, cómodo e intuitivo. Es un gran aplicación que no requiere casi nada de elementos técnicos pero que hace su función de manera excelente

Its free over Visio and will make graphs. Seriously that is the best thing about it. My workstation didn't have Visio and I needed to make some flow charts. Quick download and it works just fine. Has all the basics.