How to make an OpAmp using a Voltage-Controlled Voltage Source for the simulation purpose?

1. Create the internal circuit of an Op Amp. We use a 'VCVS' as a quick and simple Op Amp for this time. Save your circuit as 'OpAmp' before you move forward.

2. Click 'File' - "New Symbol' directly from your circuit view.

3. Draw an Op Amp shape and place the pins to the corresponding places. Keep in mind that the shape of the Op Amp does not have any electrical sense, it is just a shape and a drawing. You can draw a dog or a cat instead of a triangle there. The key things here are the three pins. The pins have the same name as the pins in your circuit (schematic), and will perform the same way as the pins in your circuit. So do not forget to right click the pins and name them as the same names in your circuit.

4. Once the drawing is done, save the symbol file as the same name as your circuit and put them in a same directory. Now open a new schematic, press 'F2' to call the library and click the drop-down menu on the top, then find the directory of your circuit and symbol. You can select the Op Amp you just created for a circuit simulation. If your directory is not showing up in the drop-down menu, try to have your new schematic file saved in the same directory as your circuit and your symbol, and then re-open LTSpice, they should show up there.

5. Here is an example of applying a sine wave to your Op Amp.