NAND logic gate

Renaud N, Joachim C (2008) Design and stability of NOR and NAND logic gates constructed with three quantum states. Phys Rev A 78 062316... 

Tanaka and Iwata1561 have described an interesting system (14) that displayed all the hallmarks of a NAND logic gate at the molecular scale. The fluorescence of the heteroaromatic unit is quenched only when Ba2+ and SCN- ions are simultaneously present at suitably high concentrations. The fluorescence-quenching PET process comes into action only when the electron-rich SCN- is held near the fluorophore by coordination to an available site on the crown-complexed Ba2+ ion. 

Fig. 7 A NAND logic gate and its corresponding truth table.

FIGURE 8.73 Electrical schematic of a CMOS NAND logic gate and its truth table. Copyright 2005 by Taylor Francis Group... 

A NAND logic gate can be understood as an integration of NOT and AND gates where the output of the AND gate becomes the input to a NOT gate. Nice molecular examples are now available. 

Figure 1.2 Circuit representation of NOR and NAND logic gates.

Fig. 12.32 Schematic representation of the three limiting equilibrium states produced from 40 and 46 seen upon treatment with appropriate ions. (Reprinted with permission from Kim, D. S. Lynch, V. M. Park, J. S. Sessler, J. L. Three Distinct Equilibrium Slates via Self-Assembly Simple Access to a Supramolecular Ion-Controlled NAND Logic Gate. J. Am. Chem. Soc. 2013, 135, 14889-14894 [88]. Copyright 2013 American Chemical Society)...

In operational terms a NAND operation can be considered as an AND logic gate with a NOT logic function imposed upon its output. The symbols used and the corresponding truth table are shown in Figure 1. 

Table 2. Truth tables for a an NAND, b an NOR, c an XOR, and d an XNOR logic gate...

Fig. 2 Truth tables and physical electronic representations of six of the 16 double-input logic gates AND, OR. NOR. NAND, INHIBIT, and XOR, [View this art in color at www.dekker.com.)...

NAND logic is also in the universal gate category, according to electronic engineers. The current inability of molecular-level counterparts to inherit this mantle has been mentioned previously in Section 2.5. NAND logic means that the output achieves the state 0 only when the inputs are both simultaneously 1. 

It is obvious to see from Table 1.5 that the input bits can be recovered by applying the gate to the output Therefore, the Toffoli gate is reversible. Now, if a basic set of gates could be built from Toffoli, then it will be demonstrated that computation can be made reversible. In fact, it is a simple matter to implement NAND from Toffoli. All we have to do is to set the target bit as 1 at the input, and Toffoli will work just as NAND. In Table 1.5, these correspond to the 2nd, 5th, 6th and 8th lines. The first two entries of these lines, plus the corresponding bits on the last column, is just NAND logic (see Table 1.6). 

In classical computation, any logical operation can be done from combinations of the logic gate nand (NOT-AND). The similar is true in quantum computing any quantum operation can be implemented using a set of universal logic gates. Such a set is composed of the Hadamard (H), controlled NOT (CNOT), phase (S) and jr/8 (T). 

Quad 2 Input NAND " Op-Amps Single Logic Gates... 

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