In Figure E6-3, which is the schematic symbol for the NOT operation (inversion)?

توضیح

Symbol 5 is a single-input triangle with an inversion bubble at its tip, the standard drawing of an inverter, which performs the NOT operation. Symbols 2 and 4 do invert, but only after a two-input AND or OR function, and symbol 6 is the exclusive-OR gate with its doubled curved input line.