Learn to design a circuit with PSpice is a task quite simple and is enough a few pages of any manual available on line to do it. What can be confusing is the number of files with different extensions that belong to this great tool of electronic simulation. This is due to the history of PSpice, which initially developed to be used in PC by Microsim passed after to OrCAD which was at last acquired by Cadence. The original CAD Microsim was Schematics. After, the program was provided with a design tool more advanced, Capture, maintaining the ability to still use Schematics.
Fortunately, the syntax used to describe a component remained the same, and all libraries with mathematical models, are the . LIB. Creating the design of a circuit with PSpice Schematics, the project will be composed of a schematic file .SCH, a control file .CIR and a circuit description file .NET both automatically generated from Schematics, and files .INC containing subcircuits, to be included in the project. The libraries containing the mathematical models to be added to the project are always .LIB, while libraries that contain graphic symbols associated with the mathematical models are the .SLB.
By using the tool of OrCAD Capture, the main project file becomes the .OPJ, and symbolic libraries are now .OLB. In short, in Schematics a component is completely defined by libraries .LIB and .SLB while in OrCAD Capture by the couple .LIB an .OLB.
Currently most of designers use OrCAD Capture for the circuits design, however, the same Capture has a tool to convert project designed with Schematics and convert .SCH and .SLB in .OPJ and .OLB. We ‘ll see how in a dedicated article.