<Tr> <Td> </Td> <Td> NOT A </Td> </Tr> <Tr> <Td> 0 </Td> <Td> </Td> </Tr> <Tr> <Td> </Td> <Td> 0 </Td> </Tr> <Tr> <Td_colspan="5"> In electronics a NOT gate is more commonly called an inverter . The circle on the symbol is called a bubble and is used in logic diagrams to indicate a logic negation between the external logic state and the internal logic state (1 to 0 or vice versa). On a circuit diagram it must be accompanied by a statement asserting that the positive logic convention or negative logic convention is being used (high voltage level = 1 or low voltage level = 1, respectively). The wedge is used in circuit diagrams to directly indicate an active - low (low voltage level = 1) input or output without requiring a uniform convention throughout the circuit diagram . This is called Direct Polarity Indication . See IEEE Std 91 / 91A and IEC 60617 - 12 . Both the bubble and the wedge can be used on distinctive - shape and rectangular - shape symbols on circuit diagrams, depending on the logic convention used . On pure logic diagrams, only the bubble is meaningful . </Td> </Tr>

List the types of standard single logic gates