The NAND Gate
The NAND, which is composed of two or more inputs and a single output, is a very popular logic element because it may be used as a universal function. That is, it may be employed to construct an inverter, an AND gate, an OR gate, or any combination of theses functions. The term NAND is formed by the concatenation NOT-AND and implies an AND function with an inverted output. The standard symbol for the NAND gate is shown in Figure 1-7 and its truth table listed in Table 1-4. The logical operation of the NAND gate is such that the output is LOW (0) only when all the inputs are HIGH (1).
Figure 1-7 Standard logic symbol for NAND gate
|
INPUT |
OUTPUT |
|
A |
B |
|
0 |
0 |
1 |
0 |
1 |
1 |
1 |
0 |
1 |
1 |
1 |
0 |
Table 1-4 Truth table for NAND gate
