Search results
Results From The WOW.Com Content Network
A CMOS transistor NAND element. V dd denotes positive voltage.. In CMOS logic, if both of the A and B inputs are high, then both the NMOS transistors (bottom half of the diagram) will conduct, neither of the PMOS transistors (top half) will conduct, and a conductive path will be established between the output and Vss (ground), bringing the output low.
Sometimes only the circle portion of the symbol is used, and it is attached to the input or output of another gate; the symbols for NAND and NOR are formed in this way. [3] A bar or overline ( ‾ ) above a variable can denote negation (or inversion or complement) performed by a NOT gate. [4] A slash (/) before the variable is also used. [3]
The 3-input Fredkin gate is functionally complete reversible gate by itself – a sole sufficient operator. There are many other three-input universal logic gates, such as the Toffoli gate . In quantum computing , the Hadamard gate and the T gate are universal, albeit with a slightly more restrictive definition than that of functional completeness.
The NAND gate has the property of functional completeness, which it shares with the NOR gate. That is, any other logic function (AND, OR, etc.) can be implemented using only NAND gates. [2] An entire processor can be created using NAND gates alone. In TTL ICs using multiple-emitter transistors, it also requires fewer transistors than a NOR gate.
The transformation is easy to describe if the circuit is wholly constructed out of 2-input NAND gates (a functionally-complete set of Boolean operators): assign every net in the circuit a variable, then for each NAND gate, construct the conjunctive normal form clauses (v 1 ∨ v 3) ∧ (v 2 ∨ v 3) ∧ (¬v 1 ∨ ¬v 2 ∨ ¬v 3), where v 1 ...
Several important complexity measures can be defined on Boolean circuits, including circuit depth, circuit size, and the number of alternations between AND gates and OR gates. For example, the size complexity of a Boolean circuit is the number of gates in the circuit. There is a natural connection between circuit size complexity and time ...
Diagram showing a way of making a logical inverter (NOT gate) from a NAND gate. Date: 22 December 2008: Source: Own work: Author: Inductiveload: Permission (Reusing this file) Own work, all rights released (Public domain)
3-input majority gate using 4 NAND gates. The 3-input majority gate output is 1 if two or more of the inputs of the majority gate are 1; output is 0 if two or more of the majority gate's inputs are 0. Thus, the majority gate is the carry output of a full adder, i.e., the majority gate is a voting machine. [7]