Oscad is a free Open Source software that has the capabilities of Circuit Drawing, PCB Layout , Circuit Simulation (Analog, Digital and Mix mode).
It is a complete CAD tool for electronics and electrical engineers. It can do almost all the task that can be performed by OrCAD therefore it is a best alternative for OrCAD users at zero price.
It provides a user friendly Graphical User Interface.
It provides facilities to create a new model and edit an existing model for an electronic component.
It provides facilities to define a new component using basic building blocks.
It gives symbolic equations and numerical values for a given circuit.
It has one unique feature i.e it can be interface with Scilab and Silab has Simple programming implementations therefore easy to understand the functioning of a circuit simulator.
If you have any Installation Issue, please refer the Installation Sheet avialable on http://www.oscad.in/resource/instruction-sheet/Oscad-Installation-Windows.pdf
If you have further any installation issue refer http://oscad.net/node/11