I am trying to understand how some of the standard ICs work in terms of simple components I understand, i.e. transistors, resistors, capacitors, and inductors (although I doubt there are any inductors in an IC.) I was trying to build and op amp from transistors, resistors, etc, and I noticed that all of these ICs are constructed with MOSFETs. In hindsight, that should have been obvious from the start. In any case, is there anyway I can use my cheap BJTs instead of buying 10 MOSFETs?