What Is An Expansion Card?

What is Expansion Card? what is an expansion slot I need to know what expansion slots are and I want a better understanding of them It says my graphics card I'm going to get (AMD Radeon r9 what is a class 2 slot machine An expansion card is a printed circuit board that can be inserted into an expansion slot on a computer's motherboard to add new functionality

what are the luckiest slot machines_ There are different kinds of slots available, one is PCI which is a general expansion slot used in the old