After simulation of this circuit, make of this circuit a subckt with a symbol of your choice two pins in and out, to which you give the same name as that of the subckt and save it in the directory lib / sym. Hint: open the netlist of your schema, then click on the right mouse button and select Edit as independant netlist, then give this file the name of your Subckt and add at the beginning of the program the name of the subkt preceded by .subckt and followed by its pins and at the end of the line, add the directive spice .ends followed by the name of the subckt. Do not forget to delete the program analysis directive, as well as the source of tension meant to control the subckt of the outside. Finally save the file under its name, then open it with word pad and save it with the extension .lib (or .sub, actually the file in question will have an extension .lib.txt) in a given directory then copy it and paste it in Lib / sub.