PGA (pin grid array) is one type of processor packaging which offers more pins than DIP( dual inline package ). It’s a square or rectangular shape package. Pins are arranged in a matrix like manner at the bottom side of the processor. Pins are generally spaced 2.54 mm (0.1″) apart, and may or may not cover the entire underside of the package.
When you don’t have data sheet of any transistor in your hand, you face trouble in determining legs of transistors. Here I will tell you, How to determine legs of a transistor using a multimeter.