For electric potential energy, the figure on my book is two parallel plates, one is positive, the other one is negative. Then a tiny positive point charge q placed near the positive plate, and then it says positive charge q has its greatest PE near positive plate. If it’s negative charge, its PE is greatest near negative plate. I understand that. But when it comes to Electric Potential, positive plate is at a higher potential than the negative plate. Why? How can we tell? Why negative charge moves from low to high potential? In my opinion, V=PE/q, so it should be the same as PE because negative charge has high PE near negative plate, so accordingly, negative plate should be the high potential when it comes to negative charge; positive plate should be the high potential when it comes to positive plate. Or it just doesn't depend on what charge it is, people just assign the positive one be the high potential. Thanks a lot for your help.