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.
This schematic diagram shows the arrangement of NOT gates within a standard 4049 CMOS hex inverting buffer. The inverter is a basic building block in digital electronics. Multiplexers, decoders, state machines, and other sophisticated digital devices may use inverters. The hex inverter is an integrated circuit that contains six inverters.
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 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 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 ...
A NOT gate, for example, can be constructed from a Toffoli gate by setting the three input bits to {a, 1, 1}, making the third output bit (1 XOR (a AND 1)) = NOT a; (a AND b) is the third output bit from {a, b, 0}. Essentially, this means that one can use Toffoli gates to build systems that will perform any desired Boolean function computation ...
An XNOR gate can be implemented using a NAND gate and an OR-AND-Invert gate, as shown in the following picture. [3] This is based on the identity ¯ (¯) ¯ An alternative, which is useful when inverted inputs are also available (for example from a flip-flop), uses a 2-2 AND-OR-Invert gate, shown on below on the right.
Schematic of basic two-input DTL NAND gate. R3, R4 and V− shift the positive output voltage of the input DL stage below the ground (to cut off the transistor at low input voltage). Diode–transistor logic ( DTL ) is a class of digital circuits that is the direct ancestor of transistor–transistor logic .