I have been googling about it and I see lots of different ways such as only flipping the signs (< becomes >) and switching variables (VGS becomes VSG). Some people even say just put absolute value without changing anything and putting absolute for threshold voltage. Which one is most accurate and easy to remember?
I know that the current ID goes from source to drain so we have to flip the AC model also.
I just need an easy hint of altering the NMOS equations for PMOS to keep in mind for my exam.