"Discrete logic" redirects here. For discrete circuitry, see Discrete circuit. For discrete TTL logic, see Transistor–transistor logic. For the former image processing company, see Discreet Logic.
A logic circuit diagram for a 4-bit carry lookahead binary adder design using only the AND, OR, and XOR logic gates.
A logic gate is a device that performs a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, one that has, for instance, zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device[1] (see ideal and real op-amps for comparison).
The primary way of building logic gates uses diodes or transistors acting as electronic switches. Today, most logic gates are made from MOSFETs (metal–oxide–semiconductor field-effect transistors).[2] They can also be constructed using vacuum tubes, electromagnetic relays with relay logic, fluidic logic, pneumatic logic, optics, molecules, acoustics,[3] or even mechanical or thermal[4] elements.
Logic gates can be cascaded in the same way that Boolean functions can be composed, allowing the construction of a physical model of all of Boolean logic, and therefore, all of the algorithms and mathematics that can be described with Boolean logic. Logic circuits include such devices as multiplexers, registers, arithmetic logic units (ALUs), and computer memory, all the way up through complete microprocessors,[5] which may contain more than 100 million logic gates.
Compound logic gates AND-OR-Invert (AOI) and OR-AND-Invert (OAI) are often employed in circuit design because their construction using MOSFETs is simpler and more efficient than the sum of the individual gates.[6]
^Jaeger (1997). Microelectronic Circuit Design. McGraw-Hill. pp. 226–233. ISBN 0-07-032482-4.
^Kanellos, Michael (2003-02-11). "Moore's Law to roll on for another decade". CNET. From Integrated circuit
^Deschamps, Jean-Pierre; Valderrama, Elena; Terés, Lluís (2016-10-12). Digital Systems: From Logic Gates to Processors. Springer. ISBN 978-3-319-41198-9.
^Tinder, Richard F. (2000). Engineering digital design (2nd ed.). Academic Press. pp. 317–319. ISBN 0-12-691295-5.
A logicgate is a device that performs a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output...
computation, a quantum logicgate (or simply quantum gate) is a basic quantum circuit operating on a small number of qubits. Quantum logicgates are the building...
XOR gate (sometimes EOR, or EXOR and pronounced as Exclusive OR) is a digital logicgate that gives a true (1 or HIGH) output when the number of true inputs...
A molecular logicgate is a molecule that performs a logical operation based on one or more physical or chemical inputs and a single output. The field...
In digital electronics, a NAND gate (NOT-AND) is a logicgate which produces an output which is false only if all its inputs are true; thus its output...
The XNOR gate (sometimes ENOR, EXNOR, NXOR, XAND and pronounced as Exclusive NOR) is a digital logicgate whose function is the logical complement of the...
The AND gate is a basic digital logicgate that implements logical conjunction (∧) from mathematical logic – AND gate behaves according to the truth table...
In gate-based quantum computing, various sets of quantum logicgates are commonly used to express quantum operations. The following tables list several...
The OR gate is a digital logicgate that implements logical disjunction. The OR gate outputs "true" if any of its inputs are "true"; otherwise it outputs...
The NOR gate is a digital logicgate that implements logical NOR - it behaves according to the truth table to the right. A HIGH output (1) results if both...
and this is referred to as NOR logic. A NAND gate is an inverted AND gate. It has the following truth table: In CMOS logic, if both of the A and B inputs...
A NOR gate or a NOT OR gate is a logicgate which gives a positive output only when both inputs are negative. Like NAND gates, NOR gates are so-called...
In logic circuits, the Toffoli gate (also CCNOT gate), invented by Tommaso Toffoli, is a universal reversible logicgate, which means that any classical...
also be implemented with the XOR gate, as A XOR 1 = Ā. Another kind of fluidic logic is bubble logic. Bubble logicgates conserve the number of bits entering...
prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) according to custom order by adding metal...
identical logicgates has value 1, then: (a) if no circuit has failed, all three circuits produce an output of value 1, and the majority gate output has...
pulses down highly dispersive waveguides. Photonic logic is the use of photons (light) in logicgates (NOT, AND, OR, NAND, NOR, XOR, XNOR). Switching is...
Diode logic (or diode-resistor logic) constructs AND and OR logicgates with diodes and resistors. An active device (vacuum tubes in early computers,...
assemblies of logicgates, often packaged in integrated circuits. Complex devices may have simple electronic representations of Boolean logic functions....
contains logic symbols. Without proper rendering support, you may see question marks, boxes, or other symbols instead of logic symbols. In logic, a set...
controlled NOT gate (also C-NOT or CNOT), controlled-X gate, controlled-bit-flip gate, Feynman gate or controlled Pauli-X is a quantum logicgate that is an...
a logic family is one of two related concepts: A logic family of monolithic digital integrated circuit devices is a group of electronic logicgates constructed...
input is a logic zero (negative power supply potential), the gate of the n-channel MOSFET is also at a negative supply voltage potential. The gate terminal...
electronics, the propagation delay, or gate delay, is the length of time which starts when the input to a logicgate becomes stable and valid to change,...
Global Information